:root {
            --primary-color: #2d8cf0;
            --bg-color: #ffffff;
            --border-color: #e8e8e8;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Arial, sans-serif;
        }

        /* 侧边栏 */
        .sidebar {
            width: 260px;
            background: var(--bg-color);
            border-right: 1px solid var(--border-color);
            padding: 20px;
            display: flex;
            flex-direction: column;
        }

        .new-chat-btn {
            padding: 12px;
            background: var(--primary-color);
            color: white;
            border: none;
            border-radius: 8px;
            cursor: pointer;
            margin-bottom: 20px;
        }

        /* 主聊天区域 */
        .main-content {
            flex: 1;
            display: flex;
            flex-direction: column;
            min-height: 700px;
            border: 2px solid black;
            border-radius: 20px;
        }

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

        .message {
            max-width: 80%;
            padding: 16px;
            border-radius: 12px;
            animation: fadeIn 0.3s ease;
        }
        .container {
            max-width: 1200px;
            margin: 0 auto;
        }
        .user-message {
            background: var(--primary-color);
            color: white;
            margin-left: auto;
        }

        .assistant-message {
            background: var(--bg-color);
            margin-right: auto;
            border: 1px solid var(--border-color);
        }

        .input-area {
            padding: 20px;
            border-top: 1px solid var(--border-color);
            display: flex;
            gap: 10px;
        }

        .chat-input {
            flex: 1;
            padding: 12px;
            border: 1px solid var(--border-color);
            border-radius: 8px;
            resize: none;
            min-height: 48px;
        }

        .send-btn {
            padding: 12px 24px;
            background: var(--primary-color);
            color: white;
            border: none;
            border-radius: 8px;
            cursor: pointer;
        }

        .loading-indicator {
            display: none;
            color: #666;
            padding: 10px;
            text-align: center;
        }
        .grid-container {
          display: grid;
          grid-template-columns: 1fr 1fr 1fr;
        }
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }