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

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            padding: 20px;
        }

        .chat-app-container {
            background: white;
            border-radius: 15px;
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
            width: 100%;
            max-width: 600px;
            height: 80vh;
            display: flex;
            flex-direction: column;
            overflow: hidden;
        }

        .header {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            padding: 20px;
            text-align: center;
        }

        .header h1 {
            font-size: 2em;
            margin-bottom: 5px;
            font-weight: 300;
        }

        .header p {
            opacity: 0.9;
            font-size: 0.9em;
        }

        .chat-container {
            flex: 1;
            display: flex;
            flex-direction: column;
            overflow: hidden;
        }

        .messages {
            flex: 1;
            padding: 20px;
            overflow-y: auto;
            display: flex;
            flex-direction: column;
            gap: 15px;
        }

        .message {
            max-width: 80%;
            padding: 12px 16px;
            border-radius: 18px;
            font-size: 0.95em;
            line-height: 1.4;
            word-wrap: break-word;
        }

        .message.bot {
            background: #f0f0f0;
            color: #333;
            align-self: flex-start;
            border-bottom-left-radius: 4px;
        }

        .message.user {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            align-self: flex-end;
            border-bottom-right-radius: 4px;
        }

        .message.typing {
            background: #f0f0f0;
            color: #666;
            font-style: italic;
            display: flex;
            align-items: center;
            gap: 8px;
        }

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

        .typing-dot {
            width: 6px;
            height: 6px;
            background: #999;
            border-radius: 50%;
            animation: typing 1.4s infinite ease-in-out;
        }

        .typing-dot:nth-child(1) { animation-delay: -0.32s; }
        .typing-dot:nth-child(2) { animation-delay: -0.16s; }

        @keyframes typing {
            0%, 80%, 100% { transform: scale(0.8); opacity: 0.5; }
            40% { transform: scale(1); opacity: 1; }
        }

        .input-container {
            padding: 20px;
            border-top: 1px solid #eee;
            display: flex;
            gap: 10px;
            align-items: flex-end;
        }

        .input-wrapper {
            flex: 1;
            position: relative;
        }

        #messageInput {
            width: 100%;
            min-height: 40px;
            max-height: 120px;
            padding: 12px 16px;
            border: 2px solid #e0e0e0;
            border-radius: 20px;
            font-size: 14px;
            font-family: inherit;
            resize: none;
            outline: none;
            transition: border-color 0.3s ease;
        }

        #messageInput:focus {
            border-color: #667eea;
        }

        #sendBtn {
            padding: 12px 20px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 20px;
            font-size: 14px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s ease;
            min-width: 60px;
        }

        #sendBtn:hover:not(:disabled) {
            transform: translateY(-1px);
            box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
        }

        #sendBtn:disabled {
            background: #ccc;
            cursor: not-allowed;
            transform: none;
        }

        .progress-indicator {
            padding: 10px 20px;
            background: #f8f9fa;
            color: #666;
            font-size: 0.8em;
            text-align: center;
            border-top: 1px solid #eee;
        }

        @media (max-width: 768px) {
            .chat-app-container {
                margin: 10px;
                height: 90vh;
            }
            
            .message {
                max-width: 90%;
            }
        }