Update app.py

app.py

@@ -19,8 +19,11 @@ def init_db():
             }, f, indent=4)
 
 def read_db():
-    with open(DB_FILE, 'r') as f:
-        return json.load(f)
+    try:
+        with open(DB_FILE, 'r') as f:
+            return json.load(f)
+    except (FileNotFoundError, json.JSONDecodeError):
+        return {"users": {}, "chatrooms": {}, "messages": {}}
 
 def write_db(data):
     with open(DB_FILE, 'w') as f:
@@ -43,18 +46,20 @@ def index():
         <link href="https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap" rel="stylesheet">
         <style>
             :root {
-                --bg-primary: #000000;
-                --bg-secondary: #101010;
-                --bg-tertiary: #1C1C1D;
-                --bg-hover: #2c2c2e;
-                --text-primary: #FFFFFF;
-                --text-secondary: #8E8E93;
-                --accent-blue: #007AFF;
-                --accent-blue-light: #3498DB;
-                --border-color: #2A2A2A;
-                --success-color: #34C759;
-                --error-color: #FF3B30;
+                --bg-primary: #0F0F11;
+                --bg-secondary: #18191C;
+                --bg-tertiary: #212328;
+                --bg-hover: #2A2C33;
+                --text-primary: #EAECEF;
+                --text-secondary: #8E9297;
+                --accent-blue: #0088CC;
+                --accent-blue-light: #33AADD;
+                --border-color: #2D2F34;
+                --success-color: #28a745;
+                --error-color: #dc3545;
                 --font-family: 'Inter', sans-serif;
+                --ton-purple: #6A5EE2;
+                --ton-purple-light: #948AE4;
             }
 
             * {
@@ -74,11 +79,9 @@ def index():
                 color: var(--text-primary);
                 overflow: hidden;
                 height: 100vh;
-                height: -webkit-fill-available;
                 width: 100vw;
                 display: flex;
-                align-items: center;
-                justify-content: center;
+                flex-direction: column;
             }
 
             .main-container {
@@ -87,25 +90,22 @@ def index():
                 display: flex;
                 flex-direction: column;
                 transition: opacity 0.3s ease;
-                background-color: var(--bg-primary);
             }
 
             #login-view {
-                display: flex;
-                flex-direction: column;
                 align-items: center;
                 justify-content: center;
                 text-align: center;
                 background: radial-gradient(circle, #1a2a3a 0%, var(--bg-primary) 70%);
             }
             #login-view img {
-                width: 120px;
-                height: 120px;
+                width: 100px;
+                height: 100px;
                 margin-bottom: 24px;
-                filter: drop-shadow(0 0 25px rgba(0, 122, 255, 0.6));
+                filter: drop-shadow(0 0 15px rgba(0, 136, 204, 0.5));
             }
             #login-view h1 {
-                font-size: 3.5rem;
+                font-size: 2.8rem;
                 font-weight: 700;
                 background: linear-gradient(45deg, var(--accent-blue-light), var(--accent-blue));
                 -webkit-background-clip: text;
@@ -113,78 +113,130 @@ def index():
                 margin-bottom: 12px;
             }
             #login-view p {
-                font-size: 1.2rem;
+                font-size: 1.1rem;
                 color: var(--text-secondary);
                 margin-bottom: 40px;
             }
 
             #app-view {
                 display: none;
+                flex-direction: column;
+                height: 100%;
+                overflow: hidden;
             }
-            
-            #main-content {
+
+            .content-area {
                 flex-grow: 1;
                 overflow: hidden;
                 position: relative;
-                display: flex;
+                padding-bottom: 60px; /* Height of nav bar */
             }
 
-            .page {
+            .view {
+                width: 100%;
+                height: 100%;
                 position: absolute;
                 top: 0;
                 left: 0;
-                width: 100%;
-                height: 100%;
-                display: flex;
+                display: none;
                 flex-direction: column;
-                opacity: 0;
-                visibility: hidden;
-                transition: opacity 0.2s ease-in-out, visibility 0.2s;
                 background-color: var(--bg-primary);
-            }
-            .page.active {
-                opacity: 1;
-                visibility: visible;
-                z-index: 10;
+                overflow-y: auto;
+                -webkit-overflow-scrolling: touch; /* Smooth scrolling on iOS */
             }
 
-            #chats-page { flex-direction: row; }
+            .view.active {
+                display: flex;
+            }
+            
+            /* Chats View Specific Styles */
+            #chats-view {
+                display: flex; /* Default display */
+                flex-direction: column;
+            }
 
-            .list-view {
+            #chatroom-list-view {
                 display: flex;
                 flex-direction: column;
                 height: 100%;
                 width: 100%;
                 background-color: var(--bg-secondary);
-                border-right: 1px solid var(--border-color);
             }
-            .page-header {
+            
+            .list-header {
                 padding: 16px;
                 border-bottom: 1px solid var(--border-color);
                 flex-shrink: 0;
-                background: rgba(28, 28, 29, 0.8);
-                backdrop-filter: blur(10px);
-                -webkit-backdrop-filter: blur(10px);
-                z-index: 5;
             }
-            .page-header-top {
+            .list-header-top {
                 display: flex;
                 justify-content: space-between;
                 align-items: center;
+                margin-bottom: 16px;
             }
-            .page-header-top h2 {
-                font-size: 1.8rem;
-                font-weight: 700;
+            .list-header-top h2 {
+                font-size: 1.5rem;
+                font-weight: 600;
+            }
+            
+            .user-profile-summary {
+                padding: 12px;
+                background-color: var(--bg-tertiary);
+                border-radius: 8px;
+                margin-bottom: 16px;
+            }
+            #user-wallet-summary, #user-nickname-summary {
+                font-size: 0.9rem;
+                color: var(--text-secondary);
+                margin-bottom: 8px;
+                word-break: break-all;
+            }
+             #user-nickname-summary { margin-bottom: 0; }
+            
+            .username-form { display: flex; gap: 8px; margin-top: 8px;}
+            .username-input {
+                flex-grow: 1;
+                background-color: var(--bg-primary);
+                border: 1px solid var(--border-color);
+                color: var(--text-primary);
+                border-radius: 6px;
+                padding: 8px 12px;
+                font-size: 0.9rem;
             }
-            .header-actions {
-                display: flex; align-items: center; gap: 8px;
+            .username-input:focus { outline: none; border-color: var(--accent-blue); }
+
+            .action-btn {
+                background: linear-gradient(45deg, var(--accent-blue), var(--accent-blue-light));
+                color: white;
+                border: none;
+                padding: 10px 16px;
+                border-radius: 6px;
+                cursor: pointer;
+                font-weight: 500;
+                transition: transform 0.2s ease, box-shadow 0.2s ease;
+                display: flex;
+                align-items: center;
+                justify-content: center;
+                gap: 8px;
+            }
+             .action-btn:disabled {
+                opacity: 0.5;
+                cursor: not-allowed;
+             }
+            .action-btn:hover:not(:disabled) {
+                transform: translateY(-2px);
+                box-shadow: 0 4px 15px rgba(0, 136, 204, 0.3);
+            }
+            .action-btn.small {
+                padding: 8px 12px;
+                font-size: 0.9rem;
             }
             
-            .scrollable-content {
+            #chatroom-list {
                 flex-grow: 1;
                 overflow-y: auto;
             }
-            .list-item {
+            .chatroom-item {
                 display: flex;
                 align-items: center;
                 gap: 12px;
@@ -193,49 +245,51 @@ def index():
                 border-bottom: 1px solid var(--border-color);
                 transition: background-color 0.2s ease;
             }
-            .list-item:hover { background-color: var(--bg-hover); }
+            .chatroom-item:hover { background-color: var(--bg-hover); }
 
             .avatar {
-                width: 48px;
-                height: 48px;
+                width: 40px;
+                height: 40px;
                 border-radius: 50%;
                 display: flex;
                 align-items: center;
                 justify-content: center;
                 font-weight: 600;
-                font-size: 1.2rem;
                 color: white;
                 flex-shrink: 0;
-            }
-            .item-info {
-                flex-grow: 1;
                 overflow: hidden;
             }
-            .item-name {
-                font-weight: 600;
-                font-size: 1.1rem;
-                white-space: nowrap;
+             .avatar.message-avatar {
+                 width: 36px;
+                 height: 36px;
+             }
+             .avatar img {
+                width: 100%;
+                height: 100%;
+                object-fit: cover;
+             }
+            .chatroom-info {
+                flex-grow: 1;
                 overflow: hidden;
-                text-overflow: ellipsis;
             }
-            .item-subtext {
-                font-size: 0.9rem;
-                color: var(--text-secondary);
+            .chatroom-name {
+                font-weight: 500;
                 white-space: nowrap;
                 overflow: hidden;
                 text-overflow: ellipsis;
             }
             .lock-icon {
-                width: 18px;
-                height: 18px;
+                width: 16px;
+                height: 16px;
                 fill: var(--text-secondary);
                 flex-shrink: 0;
             }
-            
+
             #chat-window-view {
-                display: none;
+                display: none; /* Hidden by default on mobile */
                 flex-direction: column;
-                flex-grow: 1;
+                height: 100%;
+                width: 100%;
                 background-color: var(--bg-primary);
             }
             
@@ -244,7 +298,7 @@ def index():
                 align-items: center;
                 gap: 12px;
                 padding: 12px 16px;
-                background-color: var(--bg-tertiary);
+                background-color: var(--bg-secondary);
                 border-bottom: 1px solid var(--border-color);
                 flex-shrink: 0;
             }
@@ -252,7 +306,7 @@ def index():
                 background: none;
                 border: none;
                 cursor: pointer;
-                display: none;
+                display: block; /* Shown by default on mobile */
             }
             .back-btn svg {
                 width: 24px;
@@ -273,16 +327,46 @@ def index():
                 gap: 12px;
             }
 
-            .message { display: flex; gap: 10px; max-width: 80%; }
-            .message .avatar { width: 36px; height: 36px; font-size: 1rem; align-self: flex-end; }
-            .message-content { display: flex; flex-direction: column; gap: 4px; }
-            .message-sender { font-size: 0.9rem; font-weight: 600; color: var(--text-secondary); word-break: break-all; cursor: pointer; }
-            .message-bubble { padding: 10px 14px; border-radius: 18px; line-height: 1.4; word-wrap: break-word; font-size: 1rem;}
+            .message {
+                display: flex;
+                gap: 10px;
+                max-width: 80%;
+            }
+            .message .avatar {
+                align-self: flex-end;
+            }
+            .message-content {
+                display: flex;
+                flex-direction: column;
+                gap: 4px;
+            }
+            .message-sender {
+                font-size: 0.8rem;
+                font-weight: 500;
+                color: var(--text-secondary);
+                word-break: break-all;
+                cursor: pointer;
+            }
+            .message-bubble {
+                padding: 10px 14px;
+                border-radius: 18px;
+                line-height: 1.4;
+                word-wrap: break-word;
+            }
+
             .message.sent { align-self: flex-end; flex-direction: row-reverse; }
             .message.sent .message-sender { text-align: right; color: var(--accent-blue-light); }
-            .message.sent .message-bubble { background: var(--accent-blue); color: white; border-bottom-right-radius: 4px; }
+            .message.sent .message-bubble {
+                background: linear-gradient(45deg, var(--accent-blue), var(--accent-blue-light));
+                color: white;
+                border-bottom-right-radius: 4px;
+            }
+
             .message.received { align-self: flex-start; }
-            .message.received .message-bubble { background-color: var(--bg-tertiary); border-bottom-left-radius: 4px; }
+            .message.received .message-bubble {
+                background-color: var(--bg-tertiary);
+                border-bottom-left-radius: 4px;
+            }
             
             .chat-placeholder {
                 display: flex;
@@ -293,14 +377,12 @@ def index():
                 text-align: center;
                 color: var(--text-secondary);
                 padding: 20px;
-                background-color: var(--bg-primary);
-                flex-grow: 1;
             }
             .chat-placeholder img { width: 80px; margin-bottom: 20px; opacity: 0.5; }
 
             .message-form {
                 display: flex;
-                padding: 12px 16px;
+                padding: 16px;
                 gap: 12px;
                 background-color: var(--bg-secondary);
                 border-top: 1px solid var(--border-color);
@@ -308,123 +390,224 @@ def index():
             }
             #message-input {
                 flex-grow: 1;
-                padding: 12px 18px;
-                border: none;
+                padding: 12px 16px;
+                border: 1px solid var(--border-color);
                 background-color: var(--bg-tertiary);
                 color: var(--text-primary);
                 border-radius: 22px;
                 outline: none;
                 font-size: 1rem;
+                transition: border-color 0.2s;
             }
+            #message-input:focus { border-color: var(--accent-blue); }
+
             .send-btn {
-                background: var(--accent-blue);
-                color: white;
-                border: none;
                 width: 44px;
                 height: 44px;
                 border-radius: 50%;
-                cursor: pointer;
                 flex-shrink: 0;
+                padding: 0;
+            }
+            .send-btn svg { width: 20px; height: 20px; fill: white; }
+
+            /* Users View Specific Styles */
+            #users-view .view-header {
+                padding: 16px;
+                border-bottom: 1px solid var(--border-color);
+                flex-shrink: 0;
+            }
+            #users-view .view-header h2 {
+                font-size: 1.5rem;
+                font-weight: 600;
+            }
+             #user-list {
+                 flex-grow: 1;
+                 overflow-y: auto;
+                 padding: 0 16px;
+             }
+            .user-item {
                 display: flex;
                 align-items: center;
-                justify-content: center;
-                transition: transform 0.1s ease;
+                gap: 12px;
+                padding: 12px 0;
+                cursor: pointer;
+                border-bottom: 1px solid var(--border-color);
+                transition: background-color 0.2s ease;
             }
-            .send-btn:active { transform: scale(0.9); }
-            .send-btn svg { width: 22px; height: 22px; fill: white; margin-left: 2px; }
-
-            #browser-page { flex-direction: column; background-color: var(--bg-secondary); }
-            .browser-header {
+            .user-item:last-child { border-bottom: none; }
+            .user-item:hover { background-color: var(--bg-hover); }
+            .user-item-info {
+                 flex-grow: 1;
+                 overflow: hidden;
+             }
+            .user-item-name {
+                font-weight: 500;
+                white-space: nowrap;
+                overflow: hidden;
+                text-overflow: ellipsis;
+            }
+             .user-item-address {
+                 font-size: 0.9rem;
+                 color: var(--text-secondary);
+                 white-space: nowrap;
+                 overflow: hidden;
+                 text-overflow: ellipsis;
+             }
+
+             /* Browser View Specific Styles */
+             #browser-view .view-header {
+                padding: 16px;
+                border-bottom: 1px solid var(--border-color);
+                flex-shrink: 0;
+             }
+             #browser-view .view-header h2 {
+                font-size: 1.5rem;
+                font-weight: 600;
+             }
+             .browser-bar {
                 display: flex;
                 gap: 8px;
-                padding: 12px;
-                background-color: var(--bg-tertiary);
+                padding: 12px 16px;
                 border-bottom: 1px solid var(--border-color);
+                background-color: var(--bg-tertiary);
                 flex-shrink: 0;
-            }
-            #browser-url-input {
+             }
+             .browser-url-input {
                 flex-grow: 1;
-                background-color: var(--bg-primary);
+                padding: 8px 12px;
                 border: 1px solid var(--border-color);
+                background-color: var(--bg-primary);
                 color: var(--text-primary);
-                border-radius: 8px;
-                padding: 10px;
-                font-size: 1rem;
-            }
-            #browser-frame {
+                border-radius: 6px;
+                font-size: 0.9rem;
+             }
+             .browser-url-input:focus { outline: none; border-color: var(--accent-blue); }
+             .browser-iframe {
+                width: 100%;
                 flex-grow: 1;
                 border: none;
-                background-color: white;
-            }
+             }
 
-            #profile-page {
-                align-items: center;
-                justify-content: center;
+             /* Profile View Specific Styles */
+             #profile-view {
                 padding: 24px;
+                align-items: center;
+                text-align: center;
                 overflow-y: auto;
+             }
+             #profile-view .avatar {
+                width: 80px;
+                height: 80px;
+                margin-bottom: 20px;
+             }
+             #profile-view h2 {
+                font-size: 1.8rem;
+                font-weight: 600;
+                margin-bottom: 8px;
+             }
+             #profile-view p {
+                font-size: 1rem;
+                color: var(--text-secondary);
+                margin-bottom: 8px;
+             }
+             #profile-view .action-btn {
+                margin-top: 20px;
+                width: auto;
+                padding: 12px 24px;
+             }
+            #profile-view #profile-qr-code {
+                background: white;
+                padding: 10px;
+                margin: 20px auto;
+                width: fit-content;
+                border-radius: 8px;
+            }
+            #profile-view .qr-label {
                 text-align: center;
+                color: var(--text-secondary);
+                font-size: 0.8rem;
+                margin-top: -10px;
+                margin-bottom: 20px;
             }
-            #my-profile-avatar { margin-bottom: 16px; }
-            #my-profile-username { font-size: 1.5rem; font-weight: 600; margin-bottom: 8px; }
-            #my-profile-address { font-size: 0.9rem; color: var(--text-secondary); word-break: break-all; margin-bottom: 24px; }
-            #my-profile-qr-code { background: white; padding: 10px; margin: 0 auto 24px; width: fit-content; border-radius: 8px; }
-            .username-form { display: flex; gap: 8px; margin-top: 24px; width: 100%; max-width: 400px; }
-            .username-input {
-                flex-grow: 1;
-                background-color: var(--bg-tertiary);
-                border: 1px solid var(--border-color);
-                color: var(--text-primary);
-                border-radius: 8px;
-                padding: 12px;
-                font-size: 1rem;
+            #profile-view .profile-balance {
+                 font-size: 1.1rem;
+                 font-weight: 500;
+                 margin-top: 16px;
+                 color: var(--accent-blue-light);
             }
-            .username-input:focus { outline: none; border-color: var(--accent-blue); }
 
+
+            /* Bottom Navigation Bar */
             #bottom-nav {
+                position: fixed;
+                bottom: 0;
+                left: 0;
+                width: 100%;
+                height: 60px;
+                background-color: var(--bg-secondary);
+                border-top: 1px solid var(--border-color);
                 display: flex;
                 justify-content: space-around;
-                background-color: var(--bg-tertiary);
-                border-top: 1px solid var(--border-color);
-                flex-shrink: 0;
-                padding: 5px 0;
-                z-index: 100;
+                align-items: center;
+                z-index: 500;
+                box-shadow: 0 -5px 15px rgba(0,0,0,0.2);
             }
-            .nav-btn {
-                background: none;
-                border: none;
-                color: var(--text-secondary);
-                cursor: pointer;
-                padding: 8px 12px;
+
+            .nav-item {
+                flex: 1;
                 display: flex;
                 flex-direction: column;
                 align-items: center;
-                gap: 4px;
-                font-size: 0.75rem;
-                transition: color 0.2s;
+                justify-content: center;
+                padding: 5px;
+                cursor: pointer;
+                color: var(--text-secondary);
+                transition: color 0.2s ease;
+                font-size: 0.7rem;
+                text-align: center;
+                gap: 2px;
             }
-            .nav-btn svg {
+
+            .nav-item svg {
                 width: 24px;
                 height: 24px;
                 fill: var(--text-secondary);
-                transition: fill 0.2s;
+                transition: fill 0.2s ease;
             }
-            .nav-btn.active { color: var(--accent-blue); }
-            .nav-btn.active svg { fill: var(--accent-blue); }
-            #nav-scan-btn {
-                transform: translateY(-20px);
-                background: linear-gradient(45deg, var(--accent-blue-light), var(--accent-blue));
-                width: 60px;
-                height: 60px;
-                border-radius: 50%;
-                border: 4px solid var(--bg-primary);
-                box-shadow: 0 0 20px rgba(0, 122, 255, 0.5);
+
+            .nav-item.active {
+                color: var(--accent-blue-light);
             }
-            #nav-scan-btn svg {
-                fill: white;
-                width: 30px;
-                height: 30px;
+            .nav-item.active svg {
+                fill: var(--accent-blue-light);
             }
-            
+
+            .nav-item#nav-scan {
+                flex-grow: 0;
+                width: 56px;
+                height: 56px;
+                border-radius: 50%;
+                background: linear-gradient(45deg, var(--ton-purple), var(--ton-purple-light));
+                color: white;
+                transform: translateY(-15px);
+                box-shadow: 0 5px 15px rgba(0,0,0,0.3);
+                transition: transform 0.2s ease, box-shadow 0.2s ease;
+            }
+             .nav-item#nav-scan:hover {
+                 transform: translateY(-17px);
+                 box-shadow: 0 7px 20px rgba(0,0,0,0.4);
+             }
+             .nav-item#nav-scan svg {
+                 fill: white;
+                 width: 28px;
+                 height: 28px;
+             }
+             .nav-item#nav-scan span {
+                 display: none; /* Hide text below central icon */
+             }
+
+
+            /* Modals */
             .modal-overlay {
                 position: fixed;
                 top: 0;
@@ -436,6 +619,7 @@ def index():
                 align-items: center;
                 justify-content: center;
                 z-index: 1000;
+                -webkit-backdrop-filter: blur(5px);
                 backdrop-filter: blur(5px);
             }
             .modal-content {
@@ -456,43 +640,24 @@ def index():
                 background-color: var(--bg-tertiary);
                 border: 1px solid var(--border-color);
                 color: white;
-                border-radius: 8px;
+                border-radius: 6px;
                 font-size: 1rem;
             }
             .modal-actions { display: flex; justify-content: flex-end; gap: 12px; margin-top: 8px; }
             .modal-btn {
                 padding: 10px 20px;
-                border-radius: 8px;
+                border-radius: 6px;
                 border: none;
                 cursor: pointer;
                 font-weight: 500;
+                 transition: background-color 0.2s ease;
             }
             .secondary-btn { background-color: var(--bg-hover); color: white; }
-
-            .action-btn {
-                background: var(--accent-blue);
-                color: white;
-                border: none;
-                padding: 10px 16px;
-                border-radius: 8px;
-                cursor: pointer;
-                font-weight: 500;
-                transition: background-color 0.2s ease;
-                display: flex;
-                align-items: center;
-                justify-content: center;
-                gap: 8px;
-            }
-            .action-btn:hover { background-color: var(--accent-blue-light); }
-            .action-btn.small {
-                padding: 8px 12px;
-                font-size: 0.9rem;
-                border-radius: 8px;
-            }
+             .secondary-btn:hover { background-color: #3a3d45; }
             
             #status-bar {
                 position: fixed;
-                bottom: 80px;
+                bottom: calc(60px + 20px); /* Above nav bar */
                 left: 50%;
                 transform: translateX(-50%);
                 background-color: var(--bg-tertiary);
@@ -502,7 +667,7 @@ def index():
                 font-size: 0.9rem;
                 opacity: 0;
                 visibility: hidden;
-                transition: all 0.3s;
+                transition: opacity 0.3s, visibility 0.3s;
                 z-index: 2000;
                 box-shadow: 0 5px 15px rgba(0,0,0,0.3);
             }
@@ -510,38 +675,94 @@ def index():
             #status-bar.error { background-color: var(--error-color); }
             #status-bar.visible { opacity: 1; visibility: visible; }
 
+            /* Desktop Layout (min-width 768px) */
             @media (min-width: 768px) {
+                body {
+                    align-items: center;
+                    justify-content: center;
+                }
                 .main-container {
-                    max-width: 1200px;
-                    max-height: 850px;
+                    max-width: 1100px;
+                    max-height: 800px;
                     border-radius: 12px;
                     overflow: hidden;
                     box-shadow: 0 10px 40px rgba(0,0,0,0.3);
                     border: 1px solid var(--border-color);
+                     /* Remove fixed positioning for login view */
+                     position: relative;
+                     bottom: auto;
+                     left: auto;
+                     transform: none;
+                     padding-bottom: 0; /* No nav bar padding on desktop container */
                 }
+                 #app-view {
+                     flex-direction: row; /* Side-by-side layout */
+                 }
+
+                .content-area {
+                    flex-grow: 1;
+                    padding-bottom: 0; /* No padding for desktop layout */
+                    position: static; /* Static positioning */
+                    overflow: hidden; /* Prevent content area scroll bar */
+                    display: flex; /* Use flex for side-by-side views if needed, or handle within views */
+                }
+
+                .view {
+                    position: static; /* Static positioning in desktop flex layout */
+                     overflow-y: hidden; /* Prevent individual view scroll bars unless needed */
+                }
+                 #chats-view {
+                     flex-direction: row; /* Side-by-side list and window */
+                 }
+
                 #chatroom-list-view {
-                    width: 350px;
+                    width: 320px;
                     flex-shrink: 0;
+                    border-right: 1px solid var(--border-color);
+                    display: flex !important; /* Always show list on desktop */
+                    overflow-y: auto; /* Add scroll to list view */
+                     height: 100%;
                 }
                 #chat-window-view {
-                    display: flex;
-                }
-                #chats-page.chat-active #chatroom-list-view {
-                    display: flex;
+                    width: auto;
+                    flex-grow: 1;
+                    display: flex !important; /* Always show window on desktop */
+                    overflow: hidden; /* Handle message scroll within messages-container */
+                     height: 100%;
                 }
-                .back-btn { display: none !important; }
-            }
 
-            @media (max-width: 767px) {
-                #chats-page.chat-active #chatroom-list-view {
-                    display: none;
-                }
-                #chat-window-view {
+                .back-btn { display: none !important; } /* Hide back button on desktop */
+
+                 /* Ensure other views take full space when active */
+                 #users-view.active, #browser-view.active, #profile-view.active {
                     width: 100%;
+                    height: 100%;
+                    overflow-y: auto; /* Add scroll back for these views */
+                 }
+                #users-view, #browser-view, #profile-view {
+                     /* When inactive, they are hidden by JS, no need for specific desktop hidden style */
                 }
-                .back-btn {
-                    display: block;
+
+
+                 /* Hide bottom nav bar on desktop */
+                 #bottom-nav {
+                     display: none;
+                 }
+
+                #status-bar {
+                    bottom: 20px; /* Revert status bar position */
                 }
+
+                #profile-view {
+                     padding-top: 40px; /* Adjust padding */
+                }
+                 #profile-view .avatar {
+                     width: 100px;
+                     height: 100px;
+                     margin-bottom: 24px;
+                 }
+                 #profile-view h2 { font-size: 2rem; }
+                 #profile-view p { font-size: 1.1rem; }
             }
         </style>
     </head>
@@ -555,28 +776,38 @@ def index():
         </div>
 
         <div id="app-view" class="main-container">
-            <div id="main-content">
-
-                <div id="chats-page" class="page active">
-                    <div id="chatroom-list-view" class="list-view">
-                        <div class="page-header">
-                            <div class="page-header-top">
+            <div class="content-area">
+                
+                <!-- Chats View -->
+                <div id="chats-view" class="view active">
+                    <div id="chatroom-list-view">
+                        <div class="list-header">
+                            <div class="list-header-top">
                                 <h2>Чаты</h2>
-                                <div class="header-actions">
+                                <div style="display: flex; align-items: center; gap: 8px;">
                                     <button id="create-room-show-modal" class="action-btn small">
                                         <svg xmlns="http://www.w3.org/2000/svg" height="16" viewBox="0 0 24 24" width="16" fill="white"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/></svg>
+                                        <span>Новый</span>
                                     </button>
                                 </div>
                             </div>
+                            <div class="user-profile-summary">
+                                <div id="user-wallet-summary"></div>
+                                <div id="user-nickname-summary"></div>
+                                <form class="username-form" id="username-form">
+                                    <input type="text" id="username-input" class="username-input" placeholder="Установить никнейм" autocomplete="off">
+                                    <button type="submit" class="action-btn small">✓</button>
+                                </form>
+                            </div>
                         </div>
-                        <div id="chatroom-list" class="scrollable-content"></div>
+                        <div id="chatroom-list"></div>
                     </div>
 
                     <div id="chat-window-view">
                         <div id="chat-placeholder" class="chat-placeholder">
                             <img src="https://ton.org/download/ton_symbol.svg" alt="TON Symbol">
                             <h2>Выберите чат</h2>
-                            <p>Начните общение в одном из существующих чатов или создайте свой.</p>
+                            <p>Начните общение в одном из существующих чатов или создайте свой собственный.</p>
                         </div>
                         <div id="active-chat" style="display: none; width: 100%; height: 100%; flex-direction: column;">
                             <div class="chat-header">
@@ -589,77 +820,88 @@ def index():
                             <div id="messages-container"></div>
                             <form id="message-form" class="message-form">
                                 <input type="text" id="message-input" placeholder="Сообщение..." autocomplete="off">
-                                <button type="submit" class="send-btn" id="send-btn">
-                                    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M2.01 21L23 12 2.01 3 2 10l15 2-15 2z"/></svg>
+                                <button type="submit" class="action-btn send-btn" id="send-btn">
+                                    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" width="24px" height="24px"><path d="M2.01 21L23 12 2.01 3 2 10l15 2-15 2z"/></svg>
                                 </button>
                             </form>
                         </div>
                     </div>
                 </div>
 
-                <div id="users-page" class="page">
-                    <div class="list-view">
-                        <div class="page-header">
-                            <div class="page-header-top">
-                                <h2>Пользователи</h2>
-                            </div>
-                        </div>
-                        <div id="user-list" class="scrollable-content"></div>
+                <!-- Users View -->
+                <div id="users-view" class="view">
+                    <div class="view-header">
+                        <h2>Пользователи</h2>
                     </div>
+                     <div id="user-list"></div>
                 </div>
 
-                <div id="browser-page" class="page">
-                    <div class="browser-header">
-                        <input type="text" id="browser-url-input" placeholder="https://">
-                        <button id="browser-go-btn" class="action-btn small">Go</button>
-                    </div>
-                    <iframe id="browser-frame" src="https://www.google.com/search?igu=1"></iframe>
+                <!-- Browser View -->
+                <div id="browser-view" class="view">
+                     <div class="view-header">
+                         <h2>Браузер</h2>
+                     </div>
+                     <form id="browser-form" class="browser-bar">
+                         <input type="text" id="browser-url-input" class="browser-url-input" placeholder="Введите адрес или поисковый запрос" value="https://www.google.com">
+                         <button type="submit" class="action-btn small">Go</button>
+                     </form>
+                     <iframe id="browser-iframe" class="browser-iframe" src="https://www.google.com"></iframe>
                 </div>
 
-                <div id="profile-page" class="page">
-                    <div id="my-profile-avatar" class="avatar" style="width: 100px; height: 100px; font-size: 3rem;"></div>
-                    <h3 id="my-profile-username"></h3>
-                    <p id="my-profile-address"></p>
-                    <div id="my-profile-qr-code"></div>
-                    <form class="username-form" id="username-form">
-                        <input type="text" id="username-input" class="username-input" placeholder="Ваш никнейм" autocomplete="off">
-                        <button type="submit" class="action-btn small">✓</button>
-                    </form>
+                <!-- Profile View -->
+                <div id="profile-view" class="view">
+                    <h2>Мой профиль</h2>
+                    <div id="my-profile-avatar-container" class="avatar"></div>
+                    <p id="my-profile-username"></p>
+                    <p id="my-profile-address" style="word-break: break-all;"></p>
+                     <p id="my-profile-balance" class="profile-balance"></p>
+
+                    <div id="my-profile-qr-code" style="background: white; padding: 10px; margin: 20px auto; width: fit-content; border-radius: 8px;"></div>
+                    <p class="qr-label">Отсканируйте для открытия профиля</p>
+
+                    <!-- Add buttons for actions from profile? Or keep actions in modal? -->
+                    <!-- Keeping send TON in modal for other users, maybe add other actions here later -->
+                     <button id="disconnect-wallet-btn" class="action-btn secondary-btn" style="background-color: var(--error-color); margin-top: 30px;">
+                         Отключить кошелек
+                     </button>
                 </div>
 
             </div>
 
-            <nav id="bottom-nav">
-                <button class="nav-btn active" data-page="chats-page">
-                    <svg xmlns="http://www.w3.org/2000/svg" height="24px" viewBox="0 0 24 24" width="24px"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M20 2H4c-1.1 0-2 .9-2 2v18l4-4h14c1.1 0 2-.9 2-2V4c0-1.1-.9-2-2-2zm0 14H6l-2 2V4h16v12z"/></svg>
+            <!-- Bottom Navigation -->
+            <div id="bottom-nav">
+                <div class="nav-item active" data-view="chats-view">
+                    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M20 2H4c-1.1 0-2 .9-2 2v18l4-4h14c1.1 0 2-.9 2-2V4c0-1.1-.9-2-2-2zM6 9h12v2H6V9zm8 6H6v-2h8v2zm4-6v6H6V9h12z"/></svg>
                     <span>Чаты</span>
-                </button>
-                <button class="nav-btn" data-page="users-page">
-                    <svg xmlns="http://www.w3.org/2000/svg" enable-background="new 0 0 24 24" height="24px" viewBox="0 0 24 24" width="24px"><g><rect fill="none" height="24" width="24"/></g><g><g><path d="M16,11c1.66,0,2.99-1.34,2.99-3S17.66,5,16,5C14.34,5,13,6.34,13,8S14.34,11,16,11z M8,11C9.66,11,11,9.66,11,8S9.66,5,8,5 C6.34,5,5,6.34,5,8S6.34,11,8,11z M8,13c-2.33,0-7,1.17-7,3.5V19h14v-2.5C15,14.17,10.33,13,8,13z M16,13c-0.29,0-0.62,0.02-0.97,0.05 c1.16,0.84,1.97,1.97,1.97,3.45V19h6v-2.5C23,14.17,18.33,13,16,13z"/></g></g></svg>
-                    <span>Люди</span>
-                </button>
-                <button class="nav-btn" id="nav-scan-btn">
-                    <svg xmlns="http://www.w3.org/2000/svg" height="24px" viewBox="0 0 24 24" width="24px"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M3 11h8V3H3v8zm2-6h4v4H5V5zM3 21h8v-8H3v8zm2-6h4v4H5v-4zm8-12v8h8V3h-8zm6 6h-4V5h4v4zm-2 10a2 2 0 100-4 2 2 0 000 4z"/></svg>
-                </button>
-                <button class="nav-btn" data-page="browser-page">
-                    <svg xmlns="http://www.w3.org/2000/svg" height="24px" viewBox="0 0 24 24" width="24px"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm-1 17.93c-3.95-.49-7-3.85-7-7.93 0-.62.08-1.21.21-1.79L9 15v1c0 1.1.9 2 2 2v1.93zm6.9-2.54c-.26-.81-1-1.39-1.9-1.39h-1v-3c0-.55-.45-1-1-1H8v-2h2c.55 0 1-.45 1-1V7h2c1.1 0 2-.9 2-2v-.41c2.93 1.19 5 4.06 5 7.41 0 2.08-.8 3.97-2.1 5.39z"/></svg>
+                </div>
+                <div class="nav-item" data-view="users-view">
+                    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M16.5 12c-.97 0-3.68.63-5.18 1.67-.88.61-1.41 1.35-1.82 2.33H2v3h20v-3h-8.5c.36-.74.77-1.45 1.31-2.09C14.68 12.63 15.53 12 16.5 12zM7.5 8c1.93 0 3.5-1.57 3.5-3.5S9.43 1 7.5 1 4 2.57 4 4.5 5.57 8 7.5 8zm9 0c1.93 0 3.5-1.57 3.5-3.5S18.43 1 16.5 1 13 2.57 13 4.5 14.57 8 16.5 8z"/></svg>
+                    <span>Юзеры</span>
+                </div>
+                <div class="nav-item" id="nav-scan">
+                    <svg xmlns="http://www.w3.org/2000/svg" height="24" viewBox="0 0 24 24" width="24" fill="white"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M3 11h8V3H3v8zm2-6h4v4H5V5zM3 21h8v-8H3v8zm2-6h4v4H5v-4zm8-12v8h8V3h-8zm6 6h-4V5h4v4zm-2 10a2 2 0 100-4 2 2 0 000 4z"/></svg>
+                    <span>Scan</span>
+                </div>
+                <div class="nav-item" data-view="browser-view">
+                    <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M12 2C6.48 2 2 6.48 2 12s4.48 10 10 10 10-4.48 10-10S17.52 2 12 2zm0 18c-4.41 0-8-3.59-8-8s3.59-8 8-8 8 3.59 8 8-3.59 8-8 8zm-5-5h2v-2H7v2zm3 0h2v-2h-2v2zm3 0h2v-2h-2v2z"/></svg>
                     <span>Браузер</span>
-                </button>
-                <button class="nav-btn" data-page="profile-page">
-                    <svg xmlns="http://www.w3.org/2000/svg" height="24px" viewBox="0 0 24 24" width="24px"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M12 12c2.21 0 4-1.79 4-4s-1.79-4-4-4-4 1.79-4 4 1.79 4 4 4zm0 2c-2.67 0-8 1.34-8 4v2h16v-2c0-2.66-5.33-4-8-4z"/></svg>
+                </div>
+                <div class="nav-item" data-view="profile-view">
+                    <svg xmlns="http://www.w3.org/2000/svg" height="24" viewBox="0 0 24 24" width="24" fill="white"><path d="M0 0h24v24H0V0z" fill="none"/><path d="M12 12c2.21 0 4-1.79 4-4s-1.79-4-4-4-4 1.79-4 4 1.79 4 4 4zm0 2c-2.67 0-8 1.34-8 4v2h16v-2c0-2.66-5.33-4-8-4z"/></svg>
                     <span>Профиль</span>
-                </button>
-            </nav>
+                </div>
+            </div>
         </div>
         
+        <!-- Modals -->
         <div id="create-room-modal" class="modal-overlay">
             <div class="modal-content">
                 <h3>Создать новый чат</h3>
                 <form id="create-room-form">
                     <label for="room-name">Название чата</label>
-                    <input type="text" id="room-name" required>
+                    <input type="text" id="room-name" required autocomplete="off">
                     <label for="room-password">Пароль (оставьте пустым для открытого)</label>
-                    <input type="password" id="room-password">
+                    <input type="password" id="room-password" autocomplete="new-password">
                     <div class="modal-actions">
                         <button type="button" id="create-room-cancel" class="modal-btn secondary-btn">Отмена</button>
                         <button type="submit" class="modal-btn action-btn">Создать</button>
@@ -673,7 +915,7 @@ def index():
                 <h3>Вход в приватный чат</h3>
                 <form id="password-form">
                     <label for="password-input">Введите пароль</label>
-                    <input type="password" id="password-input" required>
+                    <input type="password" id="password-input" required autocomplete="current-password">
                     <div class="modal-actions">
                         <button type="button" id="password-cancel" class="modal-btn secondary-btn">Отмена</button>
                         <button type="submit" class="modal-btn action-btn">Войти</button>
@@ -682,6 +924,7 @@ def index():
             </div>
         </div>
 
+        <!-- Profile Modal (for others' profiles) -->
         <div id="profile-modal" class="modal-overlay">
             <div class="modal-content" style="text-align: center;">
                 <h3 id="profile-modal-title">Профиль пользователя</h3>
@@ -712,39 +955,56 @@ def index():
         <script>
             document.addEventListener('DOMContentLoaded', () => {
                 const tonConnectUI = new TON_CONNECT_UI.TonConnectUI({
-                    manifestUrl: 'https://huggingface.co/spaces/Aleksmorshen/MorshenGroup/resolve/main/tonconnect-manifest.json',
+                    manifestUrl: 'https://huggingface.co/spaces/Aleksmorshen/MorshenGroup/resolve/main/tonconnect-manifest.json', // Or your manifest URL
                     buttonRootId: 'ton-connect-button'
                 });
 
-                let currentUser = { address: null, username: null };
+                let currentUser = { address: null, username: null, balance: '...' };
                 let activeChatroomId = null;
                 let messagePollingInterval = null;
                 let chatroomsData = {};
-                let usersData = {};
+                let usersData = [];
                 let html5QrCode = null;
                 let profileQrCode = null;
                 let myProfileQrCode = null;
                 
                 const loginView = document.getElementById('login-view');
                 const appView = document.getElementById('app-view');
-                const chatsPage = document.getElementById('chats-page');
+                const chatsView = document.getElementById('chats-view');
+                const usersView = document.getElementById('users-view');
+                const browserView = document.getElementById('browser-view');
+                const profileView = document.getElementById('profile-view');
+
                 const chatroomListView = document.getElementById('chatroom-list-view');
                 const chatWindowView = document.getElementById('chat-window-view');
                 const chatPlaceholder = document.getElementById('chat-placeholder');
                 const activeChat = document.getElementById('active-chat');
+
                 const profileModal = document.getElementById('profile-modal');
                 const scannerModal = document.getElementById('scanner-modal');
 
-                const AVATAR_COLORS = ['#e57373', '#81c784', '#64b5f6', '#ffb74d', '#9575cd', '#4db6ac', '#f06292', '#ff8a65', '#a1887f', '#90a4ae'];
+                const bottomNav = document.getElementById('bottom-nav');
+                const navItems = bottomNav.querySelectorAll('.nav-item');
+
+                const browserIframe = document.getElementById('browser-iframe');
+                const browserUrlInput = document.getElementById('browser-url-input');
+                const browserForm = document.getElementById('browser-form');
 
-                const getAvatar = (name, className = 'avatar') => {
+                const AVATAR_COLORS = ['#e57373', '#81c784', '#64b5f6', '#ffb74d', '#9575cd', '#4db6ac', '#f06292'];
+
+                const getAvatar = (name) => {
                     const initial = (name ? name[0] : '?').toUpperCase();
                     const charCode = initial.charCodeAt(0);
                     const color = AVATAR_COLORS[charCode % AVATAR_COLORS.length];
                     const avatar = document.createElement('div');
-                    avatar.className = className;
+                    avatar.className = 'avatar';
                     avatar.style.backgroundColor = color;
                     avatar.textContent = initial;
+                     // Basic placeholder for TON symbol if it's the app's profile/placeholder
+                    if (!name || name === 'Virton') {
+                         avatar.innerHTML = `<img src="https://ton.org/download/ton_symbol.svg" style="filter: invert(100%);">`;
+                         avatar.style.backgroundColor = 'transparent'; // Or a subtle background
+                    }
                     return avatar;
                 };
 
@@ -769,56 +1029,67 @@ def index():
                         if (response.status === 204) return null;
                         return await response.json();
                     } catch (error) {
-                        showStatus(`Ошибка: ${error.message}`, 'error');
+                        showStatus(`Ошибка API: ${error.message}`, 'error');
                         throw error;
                     }
                 };
                 
                 const truncateAddress = (address) => address ? `${address.substring(0, 4)}...${address.substring(address.length - 4)}` : '';
 
-                const showPage = (pageId) => {
-                    document.querySelectorAll('.page').forEach(p => p.classList.remove('active'));
-                    document.getElementById(pageId)?.classList.add('active');
-                    
-                    document.querySelectorAll('.nav-btn').forEach(b => b.classList.remove('active'));
-                    const navButton = document.querySelector(`.nav-btn[data-page="${pageId}"]`);
-                    if(navButton) navButton.classList.add('active');
-
-                    if(pageId === 'profile-page') renderMyProfile();
-                    if(pageId === 'users-page') fetchUsers();
+                const updateUserInfoSummary = () => {
+                    document.getElementById('user-wallet-summary').textContent = `Кошелек: ${truncateAddress(currentUser.address)}`;
+                    const nicknameEl = document.getElementById('user-nickname-summary');
+                    const usernameInput = document.getElementById('username-input');
+                    nicknameEl.textContent = currentUser.username ? `Ник: ${currentUser.username}` : `Никнейм не установлен`;
+                    usernameInput.value = currentUser.username || '';
                 };
 
-                document.querySelectorAll('.nav-btn[data-page]').forEach(button => {
-                    button.addEventListener('click', () => showPage(button.dataset.page));
-                });
-                
-                const renderMyProfile = () => {
-                    if(!currentUser.address) return;
-                    
-                    const avatarContainer = document.getElementById('my-profile-avatar');
+                 const updateMyProfileView = () => {
+                    const avatarContainer = document.getElementById('my-profile-avatar-container');
+                    const usernameEl = document.getElementById('my-profile-username');
+                    const addressEl = document.getElementById('my-profile-address');
+                    const balanceEl = document.getElementById('my-profile-balance');
+                    const qrCodeEl = document.getElementById('my-profile-qr-code');
+
                     avatarContainer.innerHTML = '';
-                    avatarContainer.appendChild(getAvatar(currentUser.username || `?`, 'avatar'));
-                    document.getElementById('my-profile-username').textContent = currentUser.username || 'Никнейм не установлен';
-                    document.getElementById('my-profile-address').textContent = currentUser.address;
-                    document.getElementById('username-input').value = currentUser.username || '';
+                    avatarContainer.appendChild(getAvatar(currentUser.username || currentUser.address));
+                    
+                    usernameEl.textContent = currentUser.username || `Пользователь ${truncateAddress(currentUser.address)}`;
+                    addressEl.textContent = currentUser.address;
+                    balanceEl.textContent = `Баланс: ${currentUser.balance}`;
 
-                    const qrCodeEl = document.getElementById('my-profile-qr-code');
                     qrCodeEl.innerHTML = '';
-                    if (myProfileQrCode) myProfileQrCode.clear();
-                    myProfileQrCode = new QRCode(qrCodeEl, {
-                        text: currentUser.address,
-                        width: 200, height: 200, colorDark : "#000000", colorLight : "#ffffff",
-                        correctLevel : QRCode.CorrectLevel.H
-                    });
-                };
+                    if (myProfileQrCode) {
+                         myProfileQrCode.clear();
+                         myProfileQrCode = null;
+                    }
+                    if (currentUser.address) {
+                        myProfileQrCode = new QRCode(qrCodeEl, {
+                            text: currentUser.address,
+                            width: 150,
+                            height: 150,
+                            colorDark : "#000000",
+                            colorLight : "#ffffff",
+                            correctLevel : QRCode.CorrectLevel.H
+                        });
+                    }
+                 }
                 
                 document.getElementById('username-form').addEventListener('submit', async (e) => {
                     e.preventDefault();
                     const newUsername = document.getElementById('username-input').value.trim();
-                    if (!newUsername || newUsername.length < 3) {
-                        showStatus('Никнейм должен быть не короче 3 символов.', 'error');
+                    if (!newUsername) {
+                        showStatus('Никнейм не может быть пустым.', 'error');
+                        return;
+                    }
+                    if (newUsername.length < 3 || newUsername.length > 20) {
+                        showStatus('Никнейм должен быть от 3 до 20 символов.', 'error');
                         return;
                     }
+                    
+                    const submitBtn = e.target.querySelector('button[type="submit"]');
+                    submitBtn.disabled = true;
+
                     try {
                         await apiCall('/api/set_username', {
                             method: 'POST',
@@ -826,15 +1097,34 @@ def index():
                             body: JSON.stringify({ address: currentUser.address, username: newUsername })
                         });
                         currentUser.username = newUsername;
+                        updateUserInfoSummary();
+                        updateMyProfileView();
                         showStatus('Никнейм успешно обновлен!', 'success');
-                        renderMyProfile();
-                        fetchChatrooms();
-                        if (activeChatroomId) fetchMessages(activeChatroomId); 
-                    } catch (err) {}
+                        fetchChatrooms(); // Update chat list with new name
+                        if (activeChatroomId) fetchMessages(activeChatroomId); // Update chat messages with new name
+                        fetchUsers(); // Update user list
+                    } catch (err) {
+                         // Error handled by apiCall
+                    } finally {
+                         submitBtn.disabled = false;
+                    }
                 });
 
                 const initializeUser = async (address) => {
                     currentUser.address = address;
+                     if (tonConnectUI.wallet) {
+                          // TON Connect UI >= 2.0 provides balance directly in wallet.account
+                          // Balance is in nanoTON, need to convert
+                         const balanceNano = tonConnectUI.wallet.account.balance;
+                         if (balanceNano !== undefined && balanceNano !== null) {
+                             currentUser.balance = (Number(balanceNano) / 1_000_000_000).toFixed(2) + ' TON';
+                         } else {
+                             currentUser.balance = 'Баланс недоступен';
+                         }
+                     } else {
+                         currentUser.balance = '...';
+                     }
+
                     try {
                         const data = await apiCall('/api/user_data', {
                             method: 'POST',
@@ -843,13 +1133,21 @@ def index():
                         });
                         currentUser.username = data.username;
                     } catch (err) {
-                        currentUser.username = null;
+                        currentUser.username = null; // User not found or error, treat as new/unknown
                     }
+                    
+                    updateUserInfoSummary();
+                    updateMyProfileView();
+
                     loginView.style.display = 'none';
                     appView.style.display = 'flex';
+                    
+                    // Initial data fetches
                     fetchChatrooms();
                     fetchUsers();
-                    showPage('chats-page');
+
+                    // Show default view (chats)
+                    showView('chats-view');
                 };
 
                 const renderChatrooms = (rooms) => {
@@ -859,15 +1157,15 @@ def index():
                     rooms.forEach(room => {
                         chatroomsData[room.id] = room;
                         const item = document.createElement('div');
-                        item.className = 'list-item';
+                        item.className = 'chatroom-item';
                         item.dataset.id = room.id;
                         
                         item.appendChild(getAvatar(room.name));
 
                         const infoDiv = document.createElement('div');
-                        infoDiv.className = 'item-info';
+                        infoDiv.className = 'chatroom-info';
                         const nameSpan = document.createElement('div');
-                        nameSpan.className = 'item-name';
+                        nameSpan.className = 'chatroom-name';
                         nameSpan.textContent = room.name;
                         infoDiv.appendChild(nameSpan);
                         item.appendChild(infoDiv);
@@ -877,67 +1175,77 @@ def index():
                             lockIcon.innerHTML = `<svg class="lock-icon" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24"><path d="M18 8h-1V6c0-2.76-2.24-5-5-5S7 3.24 7 6v2H6c-1.1 0-2 .9-2 2v10c0 1.1.9 2 2 2h12c1.1 0 2-.9 2-2V10c0-1.1-.9-2-2-2zm-6 9c-1.1 0-2-.9-2-2s.9-2 2-2 2 .9 2 2-.9 2-2 2zM9 8V6c0-1.66 1.34-3 3-3s3 1.34 3 3v2H9z"/></svg>`;
                             item.appendChild(lockIcon);
                         }
+
                         item.addEventListener('click', () => selectChatroom(room.id, room.is_private));
                         list.appendChild(item);
                     });
                 };
                 
                 const fetchChatrooms = async () => {
+                    if (!currentUser.address) return;
                     try {
                         const data = await apiCall('/api/chatrooms');
                         renderChatrooms(data.chatrooms);
-                    } catch (err) {}
+                    } catch (err) {
+                        // Error handled by apiCall
+                    }
                 };
 
-                const renderUsers = (users) => {
-                    const list = document.getElementById('user-list');
-                    list.innerHTML = '';
-                    usersData = {};
-                    users.forEach(user => {
-                        usersData[user.address] = user;
-                        const displayName = user.username || `User ${truncateAddress(user.address)}`;
-                        const item = document.createElement('div');
-                        item.className = 'list-item';
-                        item.dataset.address = user.address;
-                        
-                        item.appendChild(getAvatar(displayName));
-
-                        const infoDiv = document.createElement('div');
-                        infoDiv.className = 'item-info';
-                        const nameSpan = document.createElement('div');
-                        nameSpan.className = 'item-name';
-                        nameSpan.textContent = displayName;
-                        infoDiv.appendChild(nameSpan);
-
-                        const subtext = document.createElement('div');
-                        subtext.className = 'item-subtext';
-                        subtext.textContent = truncateAddress(user.address);
-                        infoDiv.appendChild(subtext);
-                        item.appendChild(infoDiv);
-
-                        item.addEventListener('click', () => showProfile(user.address));
-                        list.appendChild(item);
-                    });
-                }
-
-                const fetchUsers = async () => {
-                    try {
-                        const data = await apiCall('/api/users');
-                        renderUsers(data.users);
-                    } catch (err) {}
-                }
+                 const renderUsers = (users) => {
+                     const list = document.getElementById('user-list');
+                     list.innerHTML = '';
+                     usersData = users; // Store for potential future use or filtering
+                     users.forEach(user => {
+                         if (user.address === currentUser.address) return; // Don't list self
+
+                         const item = document.createElement('div');
+                         item.className = 'user-item';
+                         item.dataset.address = user.address;
+
+                         item.appendChild(getAvatar(user.username || user.address));
+
+                         const infoDiv = document.createElement('div');
+                         infoDiv.className = 'user-item-info';
+                         const nameSpan = document.createElement('div');
+                         nameSpan.className = 'user-item-name';
+                         nameSpan.textContent = user.username || `Пользователь ${truncateAddress(user.address)}`;
+                         infoDiv.appendChild(nameSpan);
+                         const addressSpan = document.createElement('div');
+                         addressSpan.className = 'user-item-address';
+                         addressSpan.textContent = user.address;
+                         infoDiv.appendChild(addressSpan);
+
+                         item.appendChild(infoDiv);
+
+                         item.addEventListener('click', () => showProfileModal(user.address));
+                         list.appendChild(item);
+                     });
+                 };
+
+                 const fetchUsers = async () => {
+                     if (!currentUser.address) return;
+                     try {
+                         const data = await apiCall('/api/users');
+                         renderUsers(data.users);
+                     } catch (err) {
+                         // Error handled by apiCall
+                     }
+                 };
 
                 const renderMessages = (messages) => {
                     const container = document.getElementById('messages-container');
-                    const shouldScroll = container.scrollTop + container.clientHeight >= container.scrollHeight - 30;
+                    // Check if user is near bottom before rendering to decide whether to auto-scroll
+                    const isNearBottom = container.scrollHeight - container.scrollTop - container.clientHeight <= 50;
+
                     container.innerHTML = '';
                     messages.forEach(msg => {
                         const msgDiv = document.createElement('div');
                         msgDiv.className = 'message ' + (msg.sender_address === currentUser.address ? 'sent' : 'received');
 
-                        const avatar = getAvatar(msg.display_name, 'avatar message-avatar');
+                        const avatar = getAvatar(msg.display_name);
+                        avatar.classList.add('message-avatar');
                         avatar.style.cursor = 'pointer';
-                        avatar.onclick = () => showProfile(msg.sender_address);
+                        avatar.onclick = () => showProfileModal(msg.sender_address);
                         
                         const contentDiv = document.createElement('div');
                         contentDiv.className = 'message-content';
@@ -945,7 +1253,7 @@ def index():
                         const senderDiv = document.createElement('div');
                         senderDiv.className = 'message-sender';
                         senderDiv.textContent = msg.display_name;
-                        senderDiv.onclick = () => showProfile(msg.sender_address);
+                        senderDiv.onclick = () => showProfileModal(msg.sender_address);
                         
                         const bubbleDiv = document.createElement('div');
                         bubbleDiv.className = 'message-bubble';
@@ -955,33 +1263,44 @@ def index():
                         contentDiv.appendChild(bubbleDiv);
 
                         msgDiv.appendChild(contentDiv);
-                        msgDiv.insertBefore(avatar, contentDiv);
+                        msgDiv.insertBefore(avatar, contentDiv); // Avatar comes first in structure
                         container.appendChild(msgDiv);
                     });
 
-                    if(shouldScroll) {
-                        container.scrollTop = container.scrollHeight;
+                    if(isNearBottom) {
+                         container.scrollTop = container.scrollHeight;
                     }
                 };
                 
                 const fetchMessages = async (roomId) => {
+                    if (!currentUser.address || !roomId) return;
                     try {
                         const data = await apiCall(`/api/messages/${roomId}`);
                         renderMessages(data.messages);
                     } catch (err) {
+                         // Error handled by apiCall
                         if (messagePollingInterval) clearInterval(messagePollingInterval);
+                        messagePollingInterval = null;
+                        showStatus('Не удалось загрузить сообщения.', 'error');
                     }
                 };
-                
-                const showChatView = () => {
+
+                const showChatWindow = () => {
+                    chatroomListView.style.display = 'none';
                     chatWindowView.style.display = 'flex';
-                    chatsPage.classList.add('chat-active');
                 };
 
-                const showListView = () => {
-                    chatsPage.classList.remove('chat-active');
-                    if (messagePollingInterval) clearInterval(messagePollingInterval);
-                    activeChatroomId = null;
+                const showChatroomList = () => {
+                    chatroomListView.style.display = 'flex';
+                    chatWindowView.style.display = 'none';
+                     // Clear active chat state
+                     activeChat.style.display = 'none';
+                     chatPlaceholder.style.display = 'flex';
+                     activeChatroomId = null;
+                     if (messagePollingInterval) {
+                         clearInterval(messagePollingInterval);
+                         messagePollingInterval = null;
+                     }
                 };
 
                 const selectChatroom = (roomId, isPrivate) => {
@@ -999,8 +1318,9 @@ def index():
 
                         chatPlaceholder.style.display = 'none';
                         activeChat.style.display = 'flex';
-                        showChatView();
                         
+                        showChatWindow(); // Switch view to chat window on mobile
+
                         fetchMessages(roomId);
                         messagePollingInterval = setInterval(() => fetchMessages(roomId), 3000);
                     };
@@ -1016,8 +1336,14 @@ def index():
                         const formSubmitHandler = async (e) => {
                             e.preventDefault();
                             passwordForm.removeEventListener('submit', formSubmitHandler);
+                             document.getElementById('password-cancel').removeEventListener('click', cancelHandler);
+
                             const password = passwordInput.value;
                             passwordModal.style.display = 'none';
+
+                            const submitBtn = e.target.querySelector('button[type="submit"]');
+                            submitBtn.disabled = true;
+
                             try {
                                 await apiCall('/api/join_chatroom', {
                                     method: 'POST',
@@ -1025,14 +1351,21 @@ def index():
                                     body: JSON.stringify({ chatroom_id: roomId, password })
                                 });
                                 proceedToRoom();
-                            } catch (err) {}
+                            } catch (err) {
+                                // Error handled by apiCall (Invalid password, etc.)
+                            } finally {
+                                submitBtn.disabled = false;
+                            }
                         };
                         passwordForm.addEventListener('submit', formSubmitHandler);
 
-                        document.getElementById('password-cancel').onclick = () => {
+                        const cancelHandler = () => {
                             passwordModal.style.display = 'none';
                             passwordForm.removeEventListener('submit', formSubmitHandler);
+                             document.getElementById('password-cancel').removeEventListener('click', cancelHandler);
                         };
+                         document.getElementById('password-cancel').addEventListener('click', cancelHandler);
+
                     } else {
                         proceedToRoom();
                     }
@@ -1043,7 +1376,7 @@ def index():
                     const input = document.getElementById('message-input');
                     const sendBtn = document.getElementById('send-btn');
                     const text = input.value.trim();
-                    if (text && activeChatroomId) {
+                    if (text && activeChatroomId && currentUser.address) {
                         input.value = '';
                         input.disabled = true;
                         sendBtn.disabled = true;
@@ -1057,8 +1390,12 @@ def index():
                                     text: text
                                 })
                             });
+                            // Fetch messages immediately after sending for faster UI update
                             await fetchMessages(activeChatroomId);
                             document.getElementById('messages-container').scrollTop = document.getElementById('messages-container').scrollHeight;
+                        } catch (err) {
+                             // Error handled by apiCall
+                            showStatus('Не удалось отправить сообщение.', 'error');
                         } finally {
                             input.disabled = false;
                             sendBtn.disabled = false;
@@ -1079,7 +1416,17 @@ def index():
                     e.preventDefault();
                     const name = document.getElementById('room-name').value.trim();
                     const password = document.getElementById('room-password').value;
-                    if (!name) return;
+                    if (!name) {
+                         showStatus('Название чата обязательно.', 'error');
+                         return;
+                    }
+                     if (!currentUser.address) {
+                         showStatus('Необходимо подключить кошелек для создания чата.', 'error');
+                         return;
+                     }
+
+                    const submitBtn = e.target.querySelector('button[type="submit"]');
+                    submitBtn.disabled = true;
 
                     try {
                         await apiCall('/api/create_chatroom', {
@@ -1090,14 +1437,15 @@ def index():
                         createRoomModal.style.display = 'none';
                         showStatus('Чат успешно создан!', 'success');
                         fetchChatrooms();
-                    } catch (err) {}
+                    } catch (err) {
+                         // Error handled by apiCall
+                    } finally {
+                         submitBtn.disabled = false;
+                    }
                 });
 
-                const showProfile = async (address) => {
-                    if (address === currentUser.address) {
-                        showPage('profile-page');
-                        return;
-                    }
+                const showProfileModal = async (address) => {
+                     if (!address) return;
                     try {
                         const userData = await apiCall('/api/user_data', {
                             method: 'POST',
@@ -1105,66 +1453,104 @@ def index():
                             body: JSON.stringify({ address: address })
                         });
                         
-                        const username = userData.username || `User ${truncateAddress(address)}`;
-                        const avatarContainer = document.getElementById('profile-avatar-container');
-                        
-                        document.getElementById('profile-modal-title').textContent = username;
-                        document.getElementById('profile-username').textContent = username;
-                        document.getElementById('profile-address').textContent = address;
+                        const username = userData.username || `Пользователь ${truncateAddress(address)}`;
                         
+                        const avatarContainer = document.getElementById('profile-avatar-container');
+                        const usernameEl = document.getElementById('profile-username');
+                        const addressEl = document.getElementById('profile-address');
+                        const qrCodeEl = document.getElementById('profile-qr-code');
+                        const sendTonBtn = document.getElementById('send-ton-btn');
+                        const modalTitle = document.getElementById('profile-modal-title');
+
+                         modalTitle.textContent = (address === currentUser.address) ? 'Мой профиль' : 'Профиль пользователя';
+
                         avatarContainer.innerHTML = '';
-                        avatarContainer.appendChild(getAvatar(username, 'avatar'));
+                        avatarContainer.appendChild(getAvatar(username));
+                        
+                        usernameEl.textContent = username;
+                        addressEl.textContent = address;
                         
-                        const qrCodeEl = document.getElementById('profile-qr-code');
                         qrCodeEl.innerHTML = '';
-                        if (profileQrCode) profileQrCode.clear();
-                        profileQrCode = new QRCode(qrCodeEl, { text: address, width: 150, height: 150 });
+                        if (profileQrCode) {
+                            profileQrCode.clear();
+                        }
+                         // Generate QR code only if address is valid
+                        if (address) {
+                             profileQrCode = new QRCode(qrCodeEl, {
+                                 text: address,
+                                 width: 150,
+                                 height: 150,
+                                 colorDark : "#000000",
+                                 colorLight : "#ffffff",
+                                 correctLevel : QRCode.CorrectLevel.H
+                             });
+                         }
                         
-                        document.getElementById('send-ton-btn').onclick = async () => {
-                            if (!tonConnectUI.connected) {
-                                showStatus('Подключите кошелек для отправки TON.', 'error'); return;
-                            }
-                            const amountString = prompt("Введите сумму в TON для отправки:", "0.1");
-                            if (amountString === null) return;
-                            const amount = parseFloat(amountString);
-                            if (isNaN(amount) || amount <= 0) {
-                                showStatus('Неверная сумма.', 'error'); return;
-                            }
-                            const transaction = {
-                                validUntil: Math.floor(Date.now() / 1000) + 600,
-                                messages: [ { address: address, amount: Math.floor(amount * 1e9).toString() } ]
+                        // Show/hide Send TON button
+                        sendTonBtn.style.display = (address === currentUser.address) ? 'none' : 'block';
+                        if (address !== currentUser.address) {
+                            sendTonBtn.onclick = async () => {
+                                if (!tonConnectUI.connected || !currentUser.address) {
+                                    showStatus('Подключите кошелек для отправки TON.', 'error');
+                                    return;
+                                }
+                                const amountString = prompt(`Введите сумму в TON для отправки на адрес ${truncateAddress(address)}:`, "0.1");
+                                if (amountString === null) return;
+                                
+                                const amount = parseFloat(amountString);
+                                if (isNaN(amount) || amount <= 0) {
+                                    showStatus('Неверная сумма.', 'error');
+                                    return;
+                                }
+                                
+                                const amountInNanoTon = Math.floor(amount * 1_000_000_000).toString();
+
+                                const transaction = {
+                                    validUntil: Math.floor(Date.now() / 1000) + 600,
+                                    messages: [ { address: address, amount: amountInNanoTon } ]
+                                };
+
+                                try {
+                                    await tonConnectUI.sendTransaction(transaction);
+                                    showStatus(`Транзакция отправлена успешно!`, 'success');
+                                    profileModal.style.display = 'none';
+                                } catch (error) {
+                                    showStatus('Транзакция отклонена или произошла ошибка.', 'error');
+                                     console.error("Send transaction failed:", error);
+                                }
                             };
-                            try {
-                                await tonConnectUI.sendTransaction(transaction);
-                                showStatus(`Транзакция отправлена успешно!`, 'success');
-                                profileModal.style.display = 'none';
-                            } catch (error) {
-                                showStatus('Транзакция отклонена.', 'error');
-                            }
-                        };
-                        
+                         }
+
                         profileModal.style.display = 'flex';
                     } catch (err) {
-                        showStatus('Не удалось загрузить профиль.', 'error');
+                        showStatus('Не удалось загрузить профиль пользователя.', 'error');
                     }
                 };
 
                 const showScanner = () => {
                     scannerModal.style.display = 'flex';
-                    html5QrCode = new Html5Qrcode("qr-reader");
+                    if (!html5QrCode) {
+                        html5QrCode = new Html5Qrcode("qr-reader");
+                    }
                     const qrCodeSuccessCallback = (decodedText, decodedResult) => {
                         hideScanner();
+                        // Basic check for TON address format (starts with EQ or UQ, length around 48 chars)
                         if (decodedText && decodedText.length > 40 && (decodedText.startsWith('EQ') || decodedText.startsWith('UQ'))) {
-                            showProfile(decodedText);
+                            showProfileModal(decodedText);
                         } else {
-                            showStatus('Отсканирован недействительный QR-код.', 'error');
+                            showStatus('Отсканирован недействительный QR-код (не похож на адрес TON).', 'error');
                         }
                     };
-                    const config = { fps: 10, qrbox: { width: 250, height: 250 } };
-                    html5QrCode.start({ facingMode: "environment" }, config, qrCodeSuccessCallback)
+                     const qrCodeErrorCallback = (errorMessage) => {
+                        // console.warn(`QR scan error: ${errorMessage}`); // Log errors but don't show modal if it's just scanning issues
+                     };
+
+                    const config = { fps: 10, qrbox: { width: 250, height: 250 }, rememberLastUsedCamera: true };
+                    html5QrCode.start({ facingMode: "environment" }, config, qrCodeSuccessCallback, qrCodeErrorCallback)
                         .catch(err => {
-                            showStatus('Не удалось запустить сканер.', 'error');
-                            hideScanner();
+                            showStatus('Не удалось запустить сканер QR-кодов. Проверьте разрешения камеры.', 'error');
+                            console.error("QR scanner start failed:", err);
+                            hideScanner(); // Hide modal if start fails
                         });
                 };
 
@@ -1175,41 +1561,165 @@ def index():
                     scannerModal.style.display = 'none';
                 };
                 
-                document.getElementById('nav-scan-btn').addEventListener('click', showScanner);
                 document.getElementById('profile-close-btn').addEventListener('click', () => profileModal.style.display = 'none');
                 document.getElementById('scanner-close-btn').addEventListener('click', hideScanner);
-                document.getElementById('back-to-list-btn').addEventListener('click', showListView);
+                document.getElementById('back-to-list-btn').addEventListener('click', showChatroomList);
                 
-                document.getElementById('browser-go-btn').addEventListener('click', () => {
-                    const input = document.getElementById('browser-url-input');
-                    let url = input.value.trim();
-                    if(url && !url.startsWith('http')) {
-                        url = 'https://' + url;
-                    }
-                    if(url) {
-                        document.getElementById('browser-frame').src = url;
-                    }
-                });
+                const handleResize = () => {
+                    const isMobile = window.innerWidth < 768;
+                    const backBtn = document.getElementById('back-to-list-btn');
+                    
+                    if (isMobile) {
+                        backBtn.style.display = 'block';
+                        // On mobile, only the active view should be displayed
+                        // Handled by showView function
+                        // If chats is the active view, manage list/window visibility
+                        if (chatsView.classList.contains('active')) {
+                             if (activeChatroomId) {
+                                 showChatWindow();
+                             } else {
+                                 showChatroomList();
+                             }
+                        } else {
+                            // Ensure chat views are hidden if another view is active
+                             chatroomListView.style.display = 'none';
+                             chatWindowView.style.display = 'none';
+                        }
+
+                    } else { // Desktop
+                        backBtn.style.display = 'none';
+                         // On desktop, chats view should always show both list and window side-by-side
+                         // Other views take full space when active.
+                         // The `display: flex !important` in CSS handles the side-by-side for chats-view
+                         // The `display: flex !important` on other views handles them taking full space
+                         // The `position: static` and overflow styles in desktop media query are key
+                         if (chatsView.classList.contains('active')) {
+                            chatroomListView.style.display = 'flex';
+                            chatWindowView.style.display = 'flex';
+                         } else {
+                            chatroomListView.style.display = 'none';
+                            chatWindowView.style.display = 'none';
+                         }
 
-                window.addEventListener('resize', () => {
-                    const isDesktop = window.innerWidth >= 768;
-                    if(isDesktop) {
-                        chatsPage.classList.remove('chat-active');
                     }
-                });
+                };
 
+                 // --- View Switching Logic ---
+                 const views = document.querySelectorAll('.view');
+                 const showView = (viewId) => {
+                     views.forEach(view => {
+                         view.classList.remove('active');
+                     });
+                     document.getElementById(viewId).classList.add('active');
+
+                     navItems.forEach(item => {
+                         item.classList.remove('active');
+                         if (item.dataset.view === viewId) {
+                             item.classList.add('active');
+                         }
+                     });
+
+                     // Special handling for Chats view layout on mobile resize
+                     if (viewId === 'chats-view') {
+                         handleResize(); // Re-apply chat list/window visibility based on size and active chat
+                     } else {
+                         // Ensure chat views are hidden when other tabs are active
+                         chatroomListView.style.display = 'none';
+                         chatWindowView.style.display = 'none';
+                         // Stop message polling if switching away from chat
+                         if (messagePollingInterval) {
+                             clearInterval(messagePollingInterval);
+                             messagePollingInterval = null;
+                         }
+                         activeChatroomId = null; // Clear active chat when leaving chat view
+                     }
+                 };
+
+                 navItems.forEach(item => {
+                     if (item.id === 'nav-scan') {
+                         item.addEventListener('click', showScanner);
+                     } else {
+                        item.addEventListener('click', () => {
+                            const viewId = item.dataset.view;
+                            if (viewId) showView(viewId);
+                        });
+                     }
+                 });
+
+                 // Browser Form Submission
+                 browserForm.addEventListener('submit', (e) => {
+                     e.preventDefault();
+                     let url = browserUrlInput.value.trim();
+                     if (!url) return;
+
+                     // Simple check if it looks like a URL (contains .) or is just text
+                     if (url.includes('.')) {
+                          // Assume it's a URL, add protocol if missing
+                         if (!url.startsWith('http://') && !url.startsWith('https://')) {
+                             url = 'https://' + url; // Default to https
+                         }
+                     } else {
+                         // Assume it's a search query, use Google search
+                         url = `https://www.google.com/search?q=${encodeURIComponent(url)}`;
+                     }
+                     browserIframe.src = url;
+                 });
+
+                 // Disconnect wallet button
+                 document.getElementById('disconnect-wallet-btn').addEventListener('click', () => {
+                      if (tonConnectUI.connected) {
+                           tonConnectUI.disconnect();
+                      }
+                 });
+
+
+                window.addEventListener('resize', handleResize);
+                
+                // Initial state check
                 tonConnectUI.onStatusChange(wallet => {
                     if (wallet) {
                         const address = TON_CONNECT_UI.toUserFriendlyAddress(wallet.account.address, false);
                         initializeUser(address);
                     } else {
-                        currentUser = { address: null, username: null };
+                        currentUser = { address: null, username: null, balance: '...' };
                         appView.style.display = 'none';
                         loginView.style.display = 'flex';
+                        // Ensure chats and messages clear on disconnect
+                        document.getElementById('chatroom-list').innerHTML = '';
+                        document.getElementById('messages-container').innerHTML = '';
+                        chatroomsData = {};
+                        usersData = [];
                         if (messagePollingInterval) clearInterval(messagePollingInterval);
+                        messagePollingInterval = null;
                         activeChatroomId = null;
+                         // Reset profile view
+                         document.getElementById('my-profile-avatar-container').innerHTML = '';
+                         document.getElementById('my-profile-username').textContent = '';
+                         document.getElementById('my-profile-address').textContent = '';
+                         document.getElementById('my-profile-balance').textContent = '';
+                         document.getElementById('my-profile-qr-code').innerHTML = '';
+                         if (myProfileQrCode) {
+                              myProfileQrCode.clear();
+                              myProfileQrCode = null;
+                         }
+
                     }
                 });
+
+                 // Handle deep links/initial wallet state on page load
+                 tonConnectUI.getWallet().then(wallet => {
+                    if (wallet) {
+                         const address = TON_CONNECT_UI.toUserFriendlyAddress(wallet.account.address, false);
+                         initializeUser(address);
+                    } else {
+                         // Show login if no wallet connected
+                         loginView.style.display = 'flex';
+                         appView.style.display = 'none';
+                    }
+                     // Set initial layout based on screen size
+                     handleResize();
+                 });
+
             });
         </script>
     </body>
@@ -1217,7 +1727,6 @@ def index():
     '''
     return Response(html_content, mimetype='text/html')
 
-
 @app.route('/api/user_data', methods=['POST'])
 def get_user_data():
     data = request.get_json()
@@ -1238,8 +1747,11 @@ def get_users():
             'address': address,
             'username': user_data.get('username')
         })
+    # Optionally sort users
+    users_list.sort(key=lambda x: x['username'] if x['username'] else x['address'])
     return jsonify({'users': users_list})
 
+
 @app.route('/api/set_username', methods=['POST'])
 def set_username():
     data = request.get_json()
@@ -1249,8 +1761,13 @@ def set_username():
         return jsonify({'error': 'Address and username are required'}), 400
     if len(username) < 3 or len(username) > 20:
         return jsonify({'error': 'Username must be between 3 and 20 characters'}), 400
-
+    
+    # Check for username uniqueness (optional but good practice)
     db = read_db()
+    for existing_address, user_data in db['users'].items():
+        if existing_address != address and user_data.get('username') == username:
+             return jsonify({'error': 'Username already taken'}), 409 # Conflict
+
     if address not in db['users']:
         db['users'][address] = {}
     db['users'][address]['username'] = username
@@ -1277,6 +1794,8 @@ def create_chatroom():
     creator_address = data.get('creator_address')
     if not name or not creator_address:
         return jsonify({'error': 'Name and creator address are required'}), 400
+    if len(name) < 3 or len(name) > 50:
+         return jsonify({'error': 'Chatroom name must be between 3 and 50 characters'}), 400
 
     db = read_db()
     room_id = str(uuid.uuid4())
@@ -1300,7 +1819,7 @@ def join_chatroom():
     if not chatroom:
         return jsonify({'error': 'Chatroom not found'}), 404
     if chatroom['is_private']:
-        if not password or not check_password_hash(chatroom['password_hash'], password):
+        if not password or not chatroom['password_hash'] or not check_password_hash(chatroom['password_hash'], password):
             return jsonify({'error': 'Invalid password'}), 403
     return jsonify({'success': True})
 
@@ -1334,6 +1853,10 @@ def send_message():
 
     if not all([chatroom_id, sender_address, text]):
         return jsonify({'error': 'Missing data'}), 400
+    if not text.strip():
+         return jsonify({'error': 'Message cannot be empty'}), 400
+    if len(text) > 1000: # Simple message length limit
+         return jsonify({'error': 'Message is too long'}), 400
 
     db = read_db()
     if chatroom_id not in db['messages']:
@@ -1342,10 +1865,11 @@ def send_message():
     message = {
         'id': str(uuid.uuid4()),
         'sender_address': sender_address,
-        'text': text,
+        'text': text.strip(),
         'timestamp': datetime.utcnow().isoformat() + "Z"
     }
     
+    # Keep only the last 100 messages per chatroom
     if len(db['messages'][chatroom_id]) >= 100:
         db['messages'][chatroom_id].pop(0)