:root {
            --primary-bg: #ffffff;
            --secondary-bg: #f5f5f5;
            --card-bg: #ffffff;
            --text-primary: #000000;
            --text-secondary: #333333;
            --text-muted: #666666;
            --border-color: #e0e0e0;
            --accent-color: #000000;
            --accent-hover: #333333;
            --danger-color: #e74c3c;
            --danger-hover: #c0392b;
            --user-bubble: #000000;
            --ai-bubble: #f0f0f0;
            --shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
        }
        [data-theme="dark"] {
            --primary-bg: #121212;
            --secondary-bg: #1e1e1e;
            --card-bg: #1e1e1e;
            --text-primary: #ffffff;
            --text-secondary: #e0e0e0;
            --text-muted: #aaaaaa;
            --border-color: #333333;
            --accent-color: #ffffff;
            --accent-hover: #cccccc;
            --danger-color: #e74c3c;
            --danger-hover: #c0392b;
            --user-bubble: #ffffff;
            --ai-bubble: #2d2d2d;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
        }
        
        body {
            background: var(--primary-bg);
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
            transition: background 0.3s;
        }
        
        .theme-toggle {
            position: fixed;
            top: 20px;
            right: 20px;
            background: var(--card-bg);
            border: 1px solid var(--border-color);
            border-radius: 50%;
            width: 40px;
            height: 40px;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            box-shadow: var(--shadow);
            z-index: 100;
            color: var(--text-primary);
        }
        
        .menu-toggle {
            position: fixed;
            top: 20px;
            left: 20px;
            background: var(--card-bg);
            border: 1px solid var(--border-color);
            border-radius: 50%;
            width: 40px;
            height: 40px;
            display: flex;
            align-items: center;
            justify-content: center;
            cursor: pointer;
            box-shadow: var(--shadow);
            z-index: 100;
            color: var(--text-primary);
        }
        
        .theme-toggle:hover, .menu-toggle:hover {
            transform: scale(1.05);
        }
        
        .sidebar {
            position: fixed;
            top: 0;
            left: -350px;
            width: 320px;
            height: 100vh;
            background: var(--card-bg);
            box-shadow: var(--shadow);
            transition: left 0.3s ease;
            z-index: 99;
            padding: 80px 20px 20px 20px;
            overflow-y: auto;
        }
        
        .sidebar.active {
            left: 0;
        }
        
        .sidebar-btn {
            width: 100%;
            padding: 12px 15px;
            background: var(--secondary-bg);
            border: none;
            border-radius: 8px;
            color: var(--text-primary);
            font-size: 0.9rem;
            cursor: pointer;
            text-align: left;
            display: flex;
            align-items: center;
            gap: 10px;
            margin-bottom: 10px;
            transition: all 0.2s;
        }
        
        .sidebar-btn:hover {
            background: var(--accent-color);
            color: var(--primary-bg);
        }
        
        .clear-btn {
            background: var(--danger-color);
            color: white;
        }
        
        .clear-btn:hover {
            background: var(--danger-hover);
        }
        
        .model-selector {
            margin-top: 20px;
            max-height: 60vh;
            overflow-y: auto;
            padding-right: 10px;
        }
        
        .model-label {
            font-size: 0.9rem;
            color: var(--text-muted);
            margin-bottom: 10px;
            display: block;
            font-weight: 600;
        }
        
        .model-option {
            width: 100%;
            padding: 10px 12px;
            background: var(--secondary-bg);
            border: 2px solid var(--border-color);
            border-radius: 8px;
            color: var(--text-primary);
            font-size: 0.85rem;
            cursor: pointer;
            margin-bottom: 8px;
            text-align: left;
            display: flex;
            align-items: center;
            gap: 10px;
            transition: all 0.2s;
        }
        
        .model-option:hover {
            background: var(--accent-color);
            color: var(--primary-bg);
            border-color: var(--accent-color);
        }
        
        .model-option.active {
            background: var(--accent-color);
            color: var(--primary-bg);
            border-color: var(--accent-color);
        }
        
        .model-option.off {
            opacity: 0.5;
            cursor: not-allowed;
        }
        
        .model-option.off:hover {
            background: var(--secondary-bg);
            color: var(--text-primary);
            border-color: var(--border-color);
        }
        
        .model-badge {
            margin-left: auto;
            font-size: 0.7rem;
            padding: 2px 6px;
            border-radius: 4px;
            background: rgba(255, 255, 255, 0.2);
        }
        
        .main-container {
            width: 100%;
            max-width: 800px;
            height: 85vh;
            background: var(--card-bg);
            border-radius: 12px;
            box-shadow: var(--shadow);
            border: 1px solid var(--border-color);
            display: flex;
            flex-direction: column;
            overflow: hidden;
        }
        
        header {
            background: var(--accent-color);
            color: var(--primary-bg);
            padding: 15px 20px;
            text-align: center;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 15px;
        }
        
        .logo-container {
            display: flex;
            align-items: center;
            gap: 15px;
        }
        
        .logo-img {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            object-fit: cover;
            border: 2px solid var(--primary-bg);
        }
        
        .logo-text {
            text-align: left;
        }
        
        .logo {
            font-size: 1.8rem;
            font-weight: 800;
            margin-bottom: 3px;
        }
        
        .tagline {
            opacity: 0.9;
            font-size: 0.85rem;
            font-weight: 500;
        }
        
        .chat-container {
            flex: 1;
            display: flex;
            flex-direction: column;
            overflow: hidden;
        }
        
        .chat-messages {
            flex: 1;
            padding: 20px;
            overflow-y: auto;
            display: flex;
            flex-direction: column;
            gap: 15px;
        }
        
        .message {
            max-width: 70%;
            padding: 12px 16px;
            border-radius: 18px;
            line-height: 1.4;
            word-wrap: break-word;
            animation: fadeIn 0.3s ease;
        }
        
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }
        
        .user-message {
            align-self: flex-end;
            background: var(--user-bubble);
            color: var(--primary-bg);
            border-bottom-right-radius: 4px;
        }
        
        .ai-message {
            align-self: flex-start;
            background: var(--ai-bubble);
            color: var(--text-primary);
            border-bottom-left-radius: 4px;
        }
        
        .message-content {
            font-size: 14px;
        }
        
        .message-time {
            font-size: 11px;
            opacity: 0.7;
            margin-top: 5px;
            text-align: right;
        }
        
        .ai-message .message-time {
            text-align: left;
        }
        
        .typing-indicator {
            align-self: flex-start;
            background: var(--ai-bubble);
            padding: 12px 16px;
            border-radius: 18px;
            display: none;
        }
        
        .typing-dots {
            display: flex;
            gap: 4px;
        }
        
        .typing-dots span {
            width: 8px;
            height: 8px;
            background: var(--text-muted);
            border-radius: 50%;
            animation: typing 1.4s infinite;
        }
        
        .typing-dots span:nth-child(2) {
            animation-delay: 0.2s;
        }
        
        .typing-dots span:nth-child(3) {
            animation-delay: 0.4s;
        }
        
        @keyframes typing {
            0%, 60%, 100% {
                transform: translateY(0);
                opacity: 0.6;
            }
            30% {
                transform: translateY(-5px);
                opacity: 1;
            }
        }
        
        .input-container {
            padding: 15px;
            border-top: 1px solid var(--border-color);
            display: flex;
            gap: 10px;
            background: var(--secondary-bg);
        }
        
        #messageInput {
            flex: 1;
            padding: 12px 16px;
            border: 2px solid var(--border-color);
            border-radius: 25px;
            font-size: 14px;
            outline: none;
            background: var(--card-bg);
            color: var(--text-primary);
        }
        
        #messageInput:focus {
            border-color: var(--accent-color);
        }
        
        #sendButton {
            padding: 12px 24px;
            background: var(--accent-color);
            color: var(--primary-bg);
            border: none;
            border-radius: 25px;
            cursor: pointer;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 8px;
            min-width: 100px;
            justify-content: center;
        }
        
        #sendButton:hover:not(:disabled) {
            background: var(--accent-hover);
        }
        
        #sendButton:disabled {
            opacity: 0.5;
            cursor: not-allowed;
        }
        
        .chat-messages::-webkit-scrollbar {
            width: 6px;
        }
        
        .chat-messages::-webkit-scrollbar-track {
            background: var(--secondary-bg);
            border-radius: 3px;
        }
        
        .chat-messages::-webkit-scrollbar-thumb {
            background: var(--border-color);
            border-radius: 3px;
        }
        
        .chat-messages::-webkit-scrollbar-thumb:hover {
            background: var(--text-muted);
        }
        
        .sidebar::-webkit-scrollbar {
            width: 6px;
        }
        
        .sidebar::-webkit-scrollbar-track {
            background: var(--secondary-bg);
            border-radius: 3px;
        }
        
        .sidebar::-webkit-scrollbar-thumb {
            background: var(--border-color);
            border-radius: 3px;
        }
        
        .sidebar::-webkit-scrollbar-thumb:hover {
            background: var(--text-muted);
        }
        
        @media (max-width: 600px) {
            .main-container {
                height: 90vh;
                border-radius: 8px;
            }
            
            .message {
                max-width: 85%;
            }
            
            .logo {
                font-size: 1.5rem;
            }
            
            .logo-img {
                width: 35px;
                height: 35px;
            }
            
            .input-container {
                padding: 12px;
            }
            
            #sendButton {
                padding: 12px 20px;
                min-width: 80px;
            }
            
            .sidebar {
                width: 300px;
                left: -300px;
            }
        }
        
        @media (max-width: 480px) {
            body {
                padding: 10px;
            }
            
            .main-container {
                height: 92vh;
            }
            
            header {
                padding: 12px 15px;
            }
            
            .logo {
                font-size: 1.3rem;
            }
            
            .chat-messages {
                padding: 15px;
            }
            
            .message {
                max-width: 90%;
                padding: 10px 14px;
            }
            
            .model-option {
                font-size: 0.8rem;
                padding: 8px 10px;
            }
        }