:root {
--primary-color: #007AFF;
--primary-hover: #0051D5;
--background: #F2F2F7;
--surface: #FFFFFF;
--surface-secondary: #F9F9F9;
--text-primary: #1C1C1E;
--text-secondary: #8E8E93;
--border-color: #C6C6C8;
--user-bubble: #007AFF;
--assistant-bubble: #E5E5EA;
--shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
--shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
--shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
--radius: 12px;
--radius-sm: 8px;
}

* {
margin: 0;
padding: 0;
box-sizing: border-box;
}

body {
font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
background: var(--background);
color: var(--text-primary);
height: 100vh;
overflow: hidden;
}

.app-container {
height: 100vh;
display: flex;
flex-direction: column;
}

.header {
background: var(--surface);
border-bottom: 1px solid var(--border-color);
backdrop-filter: blur(20px);
-webkit-backdrop-filter: blur(20px);
background: rgba(255, 255, 255, 0.72);
}

.header-content {
max-width: 800px;
margin: 0 auto;
padding: 16px 20px;
display: flex;
align-items: center;
justify-content: space-between;
}

.app-info {
display: flex;
flex-direction: column;
gap: 2px;
}

.app-title {
font-size: 20px;
font-weight: 600;
color: var(--text-primary);
}

.app-subtitle {
font-size: 13px;
color: var(--text-secondary);
font-weight: 400;
}

.built-with {
font-size: 13px;
color: var(--text-secondary);
text-decoration: none;
padding: 6px 12px;
border-radius: var(--radius-sm);
transition: all 0.2s ease;
}

.built-with:hover {
background: var(--surface-secondary);
color: var(--primary-color);
}

.chat-container {
flex: 1;
display: flex;
flex-direction: column;
max-width: 800px;
width: 100%;
margin: 0 auto;
position: relative;
}

.messages-wrapper {
flex: 1;
overflow-y: auto;
padding: 20px;
display: flex;
flex-direction: column;
}

.messages {
display: flex;
flex-direction: column;
gap: 16px;
}

.welcome-message {
max-width: 600px;
margin: 0 auto 40px;
text-align: center;
padding: 40px 20px;
}

.welcome-content {
background: var(--surface);
border-radius: 20px;
padding: 40px;
box-shadow: var(--shadow-md);
}

.welcome-icon {
font-size: 48px;
margin-bottom: 16px;
}

.welcome-content h2 {
font-size: 24px;
font-weight: 600;
margin-bottom: 8px;
color: var(--text-primary);
}

.welcome-content > p {
font-size: 16px;
color: var(--text-secondary);
margin-bottom: 32px;
line-height: 1.5;
}

.example-prompts {
margin-top: 24px;
}

.examples-title {
font-size: 14px;
color: var(--text-secondary);
margin-bottom: 12px;
font-weight: 500;
}

.example-chips {
display: flex;
flex-wrap: wrap;
gap: 8px;
justify-content: center;
}

.example-chip {
background: var(--surface-secondary);
border: 1px solid var(--border-color);
color: var(--text-primary);
padding: 8px 16px;
border-radius: 20px;
font-size: 14px;
cursor: pointer;
transition: all 0.2s ease;
font-weight: 400;
}

.example-chip:hover {
background: var(--primary-color);
color: white;
border-color: var(--primary-color);
transform: translateY(-1px);
box-shadow: var(--shadow-sm);
}

.message {
display: flex;
gap: 12px;
animation: fadeInUp 0.3s ease;
}

@keyframes fadeInUp {
from {
opacity: 0;
transform: translateY(10px);
}
to {
opacity: 1;
transform: translateY(0);
}
}

.message.user {
flex-direction: row-reverse;
}

.message-avatar {
width: 32px;
height: 32px;
border-radius: 50%;
display: flex;
align-items: center;
justify-content: center;
font-size: 14px;
font-weight: 600;
flex-shrink: 0;
}

.message.user .message-avatar {
background: var(--user-bubble);
color: white;
}

.message.assistant .message-avatar {
background: var(--assistant-bubble);
color: var(--text-primary);
}

.message-content {
max-width: 70%;
background: var(--surface);
border-radius: var(--radius);
padding: 12px 16px;
box-shadow: var(--shadow-sm);
position: relative;
}

.message.user .message-content {
background: var(--user-bubble);
color: white;
}

.message-text {
font-size: 15px;
line-height: 1.4;
white-space: pre-wrap;
word-wrap: break-word;
}

.message.user .message-text {
font-weight: 500;
}

.typing-indicator {
display: flex;
gap: 4px;
padding: 8px 0;
}

.typing-dot {
width: 8px;
height: 8px;
background: var(--text-secondary);
border-radius: 50%;
animation: typing 1.4s infinite;
}

.typing-dot:nth-child(2) {
animation-delay: 0.2s;
}

.typing-dot:nth-child(3) {
animation-delay: 0.4s;
}

@keyframes typing {
0%, 60%, 100% {
transform: translateY(0);
}
30% {
transform: translateY(-10px);
}
}

.input-container {
padding: 20px;
background: var(--surface);
border-top: 1px solid var(--border-color);
}

.input-wrapper {
display: flex;
gap: 12px;
align-items: flex-end;
background: var(--surface-secondary);
border-radius: var(--radius);
padding: 8px;
border: 1px solid var(--border-color);
transition: all 0.2s ease;
}

.input-wrapper:focus-within {
border-color: var(--primary-color);
box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
}

.message-input {
flex: 1;
border: none;
background: transparent;
font-size: 15px;
font-family: inherit;
resize: none;
outline: none;
padding: 8px 12px;
max-height: 120px;
line-height: 1.4;
color: var(--text-primary);
}

.message-input::placeholder {
color: var(--text-secondary);
}

.send-button {
width: 36px;
height: 36px;
border-radius: 50%;
border: none;
background: var(--primary-color);
color: white;
cursor: pointer;
display: flex;
align-items: center;
justify-content: center;
transition: all 0.2s ease;
flex-shrink: 0;
}

.send-button:hover:not(:disabled) {
background: var(--primary-hover);
transform: scale(1.05);
}

.send-button:disabled {
background: var(--text-secondary);
cursor: not-allowed;
opacity: 0.5;
}

.input-status {
margin-top: 8px;
text-align: center;
}

#statusText {
font-size: 12px;
color: var(--text-secondary);
}

.loading-overlay {
position: fixed;
top: 0;
left: 0;
right: 0;
bottom: 0;
background: rgba(0, 0, 0, 0.5);
backdrop-filter: blur(10px);
-webkit-backdrop-filter: blur(10px);
display: flex;
align-items: center;
justify-content: center;
z-index: 1000;
}

.loading-content {
background: var(--surface);
border-radius: 20px;
padding: 40px;
text-align: center;
max-width: 400px;
width: 90%;
box-shadow: var(--shadow-lg);
}

.loading-spinner {
width: 48px;
height: 48px;
border: 4px solid var(--surface-secondary);
border-top-color: var(--primary-color);
border-radius: 50%;
animation: spin 1s linear infinite;
margin: 0 auto 20px;
}

@keyframes spin {
to {
transform: rotate(360deg);
}
}

.loading-content h3 {
font-size: 20px;
font-weight: 600;
margin-bottom: 8px;
}

.loading-content p {
color: var(--text-secondary);
font-size: 14px;
margin-bottom: 20px;
}

.progress-bar {
height: 4px;
background: var(--surface-secondary);
border-radius: 2px;
overflow: hidden;
}

.progress-fill {
height: 100%;
background: var(--primary-color);
border-radius: 2px;
width: 0%;
transition: width 0.3s ease;
}

@media (max-width: 640px) {
.message-content {
max-width: 85%;
}

.welcome-content {
padding: 30px 20px;
}

.example-chips {
justify-content: stretch;
}

.example-chip {
flex: 1;
min-width: 0;
text-align: center;
font-size: 13px;
}
}