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

        body {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
        }

        .header {
            text-align: center;
            margin-bottom: 40px;
            color: white;
        }

        .header h1 {
            font-size: 2.5rem;
            font-weight: bold;
            margin-bottom: 10px;
            text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
        }

        .header p {
            font-size: 1.2rem;
            opacity: 0.9;
        }

        .back-btn {
            position: absolute;
            top: 20px;
            left: 20px;
            background: rgba(255,255,255,0.2);
            color: white;
            border: none;
            padding: 10px 20px;
            border-radius: 25px;
            cursor: pointer;
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 8px;
            transition: all 0.3s ease;
            backdrop-filter: blur(10px);
        }

        .back-btn:hover {
            background: rgba(255,255,255,0.3);
            transform: translateX(-5px);
        }

        .timeline {
            max-height: 70vh;
            overflow-y: auto;
            padding: 20px;
            background: rgba(255,255,255,0.95);
            border-radius: 15px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.2);
            backdrop-filter: blur(10px);
        }

        .timeline-item {
            position: relative;
            padding: 25px;
            margin-bottom: 30px;
            background: white;
            border-radius: 10px;
            box-shadow: 0 4px 15px rgba(0,0,0,0.1);
            border-left: 4px solid #667eea;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }

        .timeline-item:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(0,0,0,0.15);
        }

        .timeline-item:last-child {
            margin-bottom: 0;
        }

        .timeline-date {
            position: absolute;
            top: -10px;
            left: -20px;
            background: #667eea;
            color: white;
            padding: 8px 15px;
            border-radius: 20px;
            font-weight: bold;
            font-size: 0.9rem;
            box-shadow: 0 2px 8px rgba(0,0,0,0.2);
        }

        .timeline-content h3 {
            color: #333;
            font-size: 1.4rem;
            margin-bottom: 10px;
            font-weight: bold;
        }

        .timeline-content p {
            color: #666;
            line-height: 1.6;
            margin-bottom: 15px;
        }

        .update-features {
            list-style: none;
            padding-left: 0;
        }

        .update-features li {
            padding: 8px 0;
            border-bottom: 1px solid #f0f0f0;
            color: #555;
            position: relative;
            padding-left: 25px;
        }

        .update-features li:before {
            content: "✓";
            position: absolute;
            left: 0;
            color: #10b981;
            font-weight: bold;
        }

        .update-features li:last-child {
            border-bottom: none;
        }

        .version-badge {
            display: inline-block;
            background: #10b981;
            color: white;
            padding: 4px 12px;
            border-radius: 15px;
            font-size: 0.8rem;
            font-weight: bold;
            margin-left: 10px;
        }

        /* 滚动条样式 */
        .timeline::-webkit-scrollbar {
            width: 8px;
        }

        .timeline::-webkit-scrollbar-track {
            background: #f1f1f1;
            border-radius: 4px;
        }

        .timeline::-webkit-scrollbar-thumb {
            background: #667eea;
            border-radius: 4px;
        }

        .timeline::-webkit-scrollbar-thumb:hover {
            background: #5a6fd8;
        }

        @media (max-width: 768px) {
            .container {
                padding: 10px;
            }
            
            .header h1 {
                font-size: 2rem;
            }
            
            .timeline {
                max-height: 75vh;
                padding: 15px;
            }
            
            .timeline-item {
                padding: 20px;
            }
            
            .timeline-date {
                position: static;
                display: inline-block;
                margin-bottom: 10px;
            }
        }