* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            /* Apply Inter font globally */
            font-family: 'Inter', sans-serif;
        }

        /* CSS Variables - Light Theme (Defaults) */
        :root {
            --primary-color: #4f46e5; /* Indigo */
            --secondary-color: #6366f1; /* Lighter Indigo */
            --accent-color: #ec4899; /* Pink */
            --text-color: #1f2937; /* Dark Gray */
            --text-muted-color: #6b7280; /* Medium Gray */
            --bg-color: #f9fafb; /* Very Light Gray */
            --card-bg: #ffffff; /* White */
            --border-color: #e5e7eb; /* Light Gray */
            --chat-user-bg: #e0e7ff; /* Light Indigo */
            --chat-assistant-bg: #f3f4f6; /* Lighter Gray */
            --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
            --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
            --transition: all 0.2s ease-in-out;
            --border-radius: 0.5rem; /* 8px */
            --border-radius-lg: 0.75rem; /* 12px */
        }

        /* Dark Mode Styles - Overriding Variables */
        body.dark-mode {
            --primary-color: #6366f1; /* Lighter Indigo */
            --secondary-color: #818cf8; /* Even Lighter Indigo */
            --accent-color: #f472b6; /* Lighter Pink */
            --text-color: #e5e7eb; /* Light Gray */
            --text-muted-color: #9ca3af; /* Medium Gray */
            --bg-color: #111827; /* Very Dark Blue/Gray */
            --card-bg: #1f2937; /* Dark Gray */
            --border-color: #374151; /* Gray */
            --chat-user-bg: #3730a3; /* Dark Indigo */
            --chat-assistant-bg: #374151; /* Gray */
            --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.15);
            --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -2px rgba(0, 0, 0, 0.1);
        }

        body {
            background-color: var(--bg-color);
            color: var(--text-color);
            line-height: 1.6;
            transition: background-color var(--transition), color var(--transition);
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

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

        /* Navigation Bar */
        .navbar {
            background-color: var(--card-bg); /* Use card background for navbar in dark mode */
            color: var(--text-color);
            padding: 1rem 2rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
            box-shadow: var(--shadow);
            position: sticky;
            top: 0;
            z-index: 1000;
            border-bottom: 1px solid var(--border-color);
            transition: background-color var(--transition), border-color var(--transition);
        }

        .logo {
            font-size: 1.5rem;
            font-weight: 700; /* Bolder */
            color: var(--primary-color);
        }

        .nav-links {
            display: flex;
            align-items: center;
            gap: 1.5rem;
        }

        .nav-links a {
            color: var(--text-muted-color); /* Muted color for links */
            text-decoration: none;
            font-weight: 500;
            padding: 0.5rem 0;
            border-bottom: 2px solid transparent;
            transition: var(--transition);
        }

        .nav-links a:hover, .nav-links a.active {
            color: var(--primary-color); /* Highlight color on hover/active */
            border-bottom: 2px solid var(--primary-color);
        }

        #theme-toggle {
            background: none;
            border: none;
            color: var(--text-muted-color); /* Muted color */
            cursor: pointer;
            font-size: 1.3rem; /* Slightly larger */
            padding: 0.5rem;
            border-radius: 50%;
            transition: var(--transition);
        }
        #theme-toggle:hover {
            color: var(--text-color);
            background-color: rgba(128, 128, 128, 0.1); /* Subtle hover background */
        }


        /* Common Section Styles */
        .section {
            padding: 4rem 2rem;
            max-width: 1200px;
            margin: 0 auto;
            width: 100%;
        }

        .home-section {
            display: flex;
            flex-direction: column;
            gap: 4rem;
        }

        /* Hero Section */
        .hero {
            text-align: center;
            margin-bottom: 2rem;
        }

        .hero h1 {
            font-size: 3rem; /* Larger */
            font-weight: 700;
            margin-bottom: 1rem;
            color: var(--text-color); /* Use main text color */
            line-height: 1.2;
        }
        .hero h1 span { /* Optional: Highlight part of the title */
             color: var(--primary-color);
        }

        .hero p {
            font-size: 1.2rem;
            margin-bottom: 2.5rem; /* More space */
            color: var(--text-muted-color);
            max-width: 600px; /* Constrain width */
            margin-left: auto;
            margin-right: auto;
        }

        .cta-button {
            display: inline-block;
            background-color: var(--primary-color); /* Use primary color */
            color: white;
            padding: 0.9rem 1.8rem; /* Slightly larger padding */
            border-radius: var(--border-radius);
            text-decoration: none;
            font-weight: 600; /* Bolder */
            transition: var(--transition);
            box-shadow: var(--shadow);
        }

        .cta-button:hover {
            background-color: var(--secondary-color); /* Use secondary on hover */
            transform: translateY(-2px);
            box-shadow: var(--shadow-lg);
        }

        /* Features Section */
        .features {
            display: grid; /* Use grid for better alignment */
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); /* Responsive grid */
            gap: 2rem;
            margin: 3rem 0;
        }

        .feature-card {
            background-color: var(--card-bg);
            border-radius: var(--border-radius-lg); /* Larger radius */
            padding: 2.5rem; /* More padding */
            box-shadow: var(--shadow);
            text-align: center;
            transition: var(--transition);
            border: 1px solid var(--border-color); /* Subtle border */
        }

        .feature-card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-lg);
            border-color: var(--primary-color); /* Highlight border on hover */
        }

        .feature-card i {
            font-size: 2.8rem; /* Larger icon */
            color: var(--primary-color);
            margin-bottom: 1.5rem; /* More space */
            display: inline-block; /* Needed for potential transforms */
        }

        .feature-card h3 {
            margin-bottom: 1rem;
            color: var(--text-color); /* Use text color */
            font-size: 1.25rem;
            font-weight: 600;
        }
        .feature-card p {
            color: var(--text-muted-color);
            font-size: 0.95rem;
        }

        /* Tech Stack Section */
        .tech-stack {
            text-align: center;
            margin-top: 3rem;
        }

        .tech-stack h2 {
            margin-bottom: 2rem; /* More space */
            color: var(--text-color);
            font-size: 1.75rem;
            font-weight: 600;
        }

        .tech-icons {
            display: flex;
            justify-content: center;
            flex-wrap: wrap;
            gap: 3rem; /* More gap */
        }

        .tech-icon {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 0.8rem; /* More gap */
            transition: var(--transition);
        }
         .tech-icon:hover {
             transform: scale(1.1); /* Add subtle hover effect */
         }

        .tech-icon i {
            font-size: 2.5rem; /* Larger icons */
            color: var(--text-muted-color);
            transition: var(--transition);
        }
        .tech-icon:hover i {
            color: var(--primary-color); /* Highlight icon on hover */
        }
        .tech-icon span {
            font-size: 0.9rem;
            color: var(--text-muted-color);
            font-weight: 500;
        }

        /* Chat Section */
        .chat-section {
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: calc(100vh - 150px); /* Adjust based on nav/footer height */
            padding: 2rem 1rem; /* Padding for smaller screens */
        }

        .chat-container {
            background-color: var(--card-bg);
            border-radius: var(--border-radius-lg);
            box-shadow: var(--shadow-lg); /* More prominent shadow */
            width: 100%;
            max-width: 800px;
            height: 70vh; /* Use viewport height */
            max-height: 700px; /* Max height */
            display: flex;
            flex-direction: column;
            overflow: hidden;
            border: 1px solid var(--border-color);
        }

        .chat-header {
            padding: 1rem 1.5rem; /* More padding */
            background-color: var(--card-bg); /* Match card background */
            color: var(--text-color);
            display: flex;
            justify-content: space-between;
            align-items: center;
            border-bottom: 1px solid var(--border-color);
        }
        .chat-header h2 {
            font-weight: 600;
            font-size: 1.2rem;
        }

        .model-selector {
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        .model-selector label {
            font-size: 0.9rem;
            color: var(--text-muted-color);
            font-weight: 500;
        }

        #model-select {
            padding: 0.4rem 0.8rem; /* Adjust padding */
            border: 1px solid var(--border-color);
            border-radius: var(--border-radius);
            background-color: var(--bg-color); /* Use background color */
            color: var(--text-color);
            font-size: 0.9rem;
            cursor: pointer;
            transition: var(--transition);
        }
        #model-select:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 2px rgba(var(--primary-color-rgb, 79 70 229), 0.3); /* Focus ring */
        }
        /* Add RGB version of primary color for focus ring */
        body { --primary-color-rgb: 79, 70, 229; }
        body.dark-mode { --primary-color-rgb: 99, 102, 241; }


        .chat-messages {
            flex: 1;
            padding: 1.5rem; /* More padding */
            overflow-y: auto;
            display: flex;
            flex-direction: column;
            gap: 1rem;
            /* Custom scrollbar (optional) */
            scrollbar-width: thin;
            scrollbar-color: var(--secondary-color) var(--card-bg);
        }
        .chat-messages::-webkit-scrollbar {
            width: 8px;
        }
        .chat-messages::-webkit-scrollbar-track {
            background: var(--card-bg);
        }
        .chat-messages::-webkit-scrollbar-thumb {
            background-color: var(--secondary-color);
            border-radius: 10px;
            border: 2px solid var(--card-bg);
        }


        .message {
            max-width: 80%;
            padding: 0.8rem 1.2rem; /* Adjust padding */
            border-radius: var(--border-radius-lg); /* Match container radius */
            line-height: 1.5;
            word-wrap: break-word; /* Ensure long words break */
        }

        .user-message {
            align-self: flex-end;
            background-color: var(--chat-user-bg);
            color: #ffffff; /* White text on dark user bg */
            border-bottom-right-radius: 0.25rem; /* Slightly different corner */
        }

        .assistant-message {
            align-self: flex-start;
            background-color: var(--chat-assistant-bg);
            color: var(--text-color);
            border-bottom-left-radius: 0.25rem; /* Slightly different corner */
        }

        .system-message {
            align-self: center;
            background-color: var(--secondary-color);
            color: white;
            text-align: center;
            font-size: 0.85rem;
            padding: 0.5rem 1rem;
            border-radius: var(--border-radius);
            max-width: 90%;
        }

        .message-content {
            font-size: 0.95rem; /* Slightly smaller message font */
        }

        /* Code block styling */
        .message-content pre {
            background-color: rgba(0, 0, 0, 0.2); /* Darker background for code */
            padding: 0.8rem;
            border-radius: var(--border-radius);
            overflow-x: auto;
            margin: 0.75rem 0;
            font-size: 0.85rem; /* Smaller font for code */
            border: 1px solid var(--border-color);
            scrollbar-width: thin;
            scrollbar-color: var(--secondary-color) rgba(0, 0, 0, 0.2);
        }
        .message-content pre::-webkit-scrollbar { height: 6px; }
        .message-content pre::-webkit-scrollbar-thumb { background-color: var(--secondary-color); border-radius: 3px; }

        .message-content code:not(pre code) { /* Inline code */
            background-color: rgba(0, 0, 0, 0.2);
            padding: 0.2em 0.4em;
            border-radius: 4px;
            font-size: 0.85em;
            color: var(--accent-color); /* Use accent color for inline code */
        }
        body.dark-mode .message-content pre {
             background-color: rgba(0, 0, 0, 0.3); /* Even darker in dark mode */
             border: 1px solid #4b5563; /* Slightly darker border */
        }
         body.dark-mode .message-content code {
              color: var(--accent-color);
         }

        /* Typing indicator */
        .typing-indicator {
            padding: 0.5rem 1rem;
            display: flex; /* Align dots nicely */
            align-items: center;
        }

        .typing-dots {
            display: flex;
            gap: 5px; /* Slightly more gap */
        }

        .typing-dots span {
            width: 9px; /* Slightly larger dots */
            height: 9px;
            background-color: var(--text-muted-color); /* Use muted color */
            border-radius: 50%;
            display: inline-block;
            opacity: 0.7;
            animation: typing-dot 1.4s infinite ease-in-out; /* Smoother animation */
        }

        /* Animation delays */
        .typing-dots span:nth-child(1) { animation-delay: 0s; }
        .typing-dots span:nth-child(2) { animation-delay: 0.2s; }
        .typing-dots span:nth-child(3) { animation-delay: 0.4s; }

        @keyframes typing-dot {
            0%, 60%, 100% { transform: translateY(0) scale(1); opacity: 0.7; }
            30% { transform: translateY(-5px) scale(1.1); opacity: 1; } /* More pronounced bounce */
        }

        .chat-input {
            padding: 1rem 1.5rem; /* More padding */
            display: flex;
            gap: 0.8rem; /* More gap */
            border-top: 1px solid var(--border-color);
            background-color: var(--card-bg); /* Match chat background */
        }

        #user-input {
            flex: 1;
            padding: 0.8rem 1rem; /* Adjust padding */
            border: 1px solid var(--border-color);
            border-radius: var(--border-radius);
            resize: none;
            font-size: 1rem;
            background-color: var(--bg-color); /* Use main bg for input */
            color: var(--text-color);
            transition: var(--transition);
            min-height: 44px; /* Ensure minimum height */
            max-height: 150px; /* Limit expansion */
            overflow-y: auto; /* Add scroll if needed */
            scrollbar-width: thin;
        }

        #user-input:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 2px rgba(var(--primary-color-rgb), 0.3); /* Focus ring */
            background-color: var(--card-bg); /* Change bg on focus */
        }

        #send-button {
            background-color: var(--primary-color);
            color: white;
            border: none;
            border-radius: var(--border-radius);
            padding: 0 1.2rem; /* Adjust padding */
            cursor: pointer;
            transition: var(--transition);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.1rem; /* Icon size */
        }

        #send-button:hover {
            background-color: var(--secondary-color);
            transform: scale(1.05); /* Slight scale on hover */
        }
        #send-button:disabled { /* Style for disabled state */
            opacity: 0.6;
            cursor: not-allowed;
        }


        /* Admin Panel Styles - Applying Dark Theme */
        .admin-page {
            padding: 2rem;
            max-width: 1000px;
            margin: 2rem auto; /* Center admin page */
        }

        .admin-page h1 {
            margin-bottom: 2rem;
            color: var(--text-color); /* Use text color */
            font-size: 2rem;
            font-weight: 700;
            border-bottom: 1px solid var(--border-color);
            padding-bottom: 1rem;
        }

        .admin-section {
            background-color: var(--card-bg);
            border-radius: var(--border-radius-lg);
            padding: 2rem; /* More padding */
            margin-bottom: 2rem;
            box-shadow: var(--shadow);
            border: 1px solid var(--border-color);
        }

        .admin-section h2 {
            margin-bottom: 1.5rem; /* More space */
            color: var(--primary-color); /* Use primary color for headings */
            font-size: 1.5rem;
            font-weight: 600;
        }

        /* Style form elements consistently */
        .admin-section select,
        .admin-section input[type="text"],
        .admin-section input[type="number"],
        .admin-section textarea {
            padding: 0.6rem 0.8rem;
            border: 1px solid var(--border-color);
            border-radius: var(--border-radius);
            margin-right: 0.5rem;
            background-color: var(--bg-color); /* Use main bg */
            color: var(--text-color);
            font-size: 0.95rem;
            transition: var(--transition);
            width: auto; /* Allow natural width or set specific widths */
            min-width: 150px; /* Minimum width */
        }
        .admin-section input[type="text"],
        .admin-section textarea {
             width: 100%; /* Make text inputs wider */
             max-width: 400px;
        }

        .admin-section select:focus,
        .admin-section input:focus,
        .admin-section textarea:focus {
            outline: none;
            border-color: var(--primary-color);
            box-shadow: 0 0 0 2px rgba(var(--primary-color-rgb), 0.3);
            background-color: var(--card-bg);
        }

        .admin-section button {
            background-color: var(--primary-color);
            color: white;
            border: none;
            border-radius: var(--border-radius);
            padding: 0.6rem 1.2rem; /* Consistent padding */
            cursor: pointer;
            transition: var(--transition);
            font-weight: 500;
        }

        .admin-section button:hover {
            background-color: var(--secondary-color);
            transform: translateY(-1px);
        }
        .admin-section button.delete-button { /* Specific style for delete */
            background-color: var(--accent-color);
        }
        .admin-section button.delete-button:hover {
            background-color: #d94682; /* Darker pink */
        }


        /* Lists in Admin Panel */
        #rules-list, #active-chats {
            list-style: none;
            margin: 1.5rem 0; /* More margin */
            padding: 0;
        }

        #rules-list li, #active-chats li {
            margin-bottom: 0.8rem; /* More space */
            padding: 1rem; /* More padding */
            background-color: var(--bg-color); /* Use main bg */
            border-radius: var(--border-radius);
            display: flex;
            justify-content: space-between;
            align-items: center;
            border: 1px solid var(--border-color);
            transition: var(--transition);
        }
        #rules-list li:hover, #active-chats li:hover {
            background-color: var(--card-bg); /* Change bg on hover */
            border-color: var(--secondary-color);
        }

        #active-chats a {
            color: var(--primary-color);
            text-decoration: none;
            font-weight: 500;
        }

        #active-chats a:hover {
            text-decoration: underline;
            color: var(--secondary-color);
        }

        /* Admin Chat History Viewer */
        .admin-chat-history {
            max-height: 450px; /* Increased height */
            overflow-y: auto;
            padding: 1.5rem; /* More padding */
            background-color: var(--bg-color); /* Use main bg */
            border-radius: var(--border-radius);
            margin-top: 1.5rem;
            border: 1px solid var(--border-color);
            /* Custom scrollbar */
            scrollbar-width: thin;
            scrollbar-color: var(--secondary-color) var(--bg-color);
        }
        .admin-chat-history::-webkit-scrollbar { width: 8px; }
        .admin-chat-history::-webkit-scrollbar-track { background: var(--bg-color); }
        .admin-chat-history::-webkit-scrollbar-thumb { background-color: var(--secondary-color); border-radius: 10px; border: 2px solid var(--bg-color); }


        .admin-message {
            padding: 0.8rem 1rem;
            margin-bottom: 0.8rem;
            border-radius: var(--border-radius);
            font-size: 0.9rem;
            line-height: 1.5;
        }

        .admin-message.user-message {
            background-color: var(--chat-user-bg);
            color: white; /* Ensure contrast */
            margin-left: 20%; /* Indent user messages */
        }

        .admin-message.assistant-message {
            background-color: var(--chat-assistant-bg);
            color: var(--text-color);
            margin-right: 20%; /* Indent assistant messages */
        }
        .admin-message strong { /* Add role indicator */
            font-weight: 600;
            margin-right: 0.5em;
            display: block; /* Put role on its own line */
            margin-bottom: 0.25em;
            font-size: 0.8em;
            opacity: 0.8;
        }

        /* Footer */
        .footer {
            background-color: var(--card-bg); /* Match navbar */
            color: var(--text-muted-color);
            text-align: center;
            padding: 1.5rem; /* More padding */
            margin-top: auto;
            border-top: 1px solid var(--border-color);
            font-size: 0.9rem;
        }
        body.dark-mode .footer {
             background-color: #111827; /* Match dark bg */
        }

        /* Responsive Styles */
        @media (max-width: 768px) {
            .section {
                padding: 3rem 1rem; /* Adjust padding */
            }
            .navbar {
                padding: 1rem;
            }
            .nav-links {
                gap: 1rem; /* Reduce gap */
            }
            .hero h1 {
                font-size: 2.2rem; /* Adjust font size */
            }
            .hero p {
                font-size: 1rem;
            }
            .features {
                grid-template-columns: 1fr; /* Stack features */
            }
            .chat-container {
                height: calc(100vh - 120px); /* Adjust height for mobile */
                max-height: none;
                border-radius: 0; /* Full width on mobile */
                border-left: none;
                border-right: none;
            }
            .chat-messages {
                padding: 1rem;
            }
            .message {
                max-width: 90%;
                padding: 0.7rem 1rem;
            }
            .chat-input {
                padding: 0.8rem 1rem;
            }
            .admin-page {
                padding: 1rem;
                margin: 1rem auto;
            }
            .admin-section {
                padding: 1.5rem;
            }
            .admin-section h2 {
                font-size: 1.3rem;
            }
            .admin-message {
                 margin-left: 5%;
                 margin-right: 5%;
            }
        }