/* 样式开始 */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: 'Microsoft YaHei', Arial, sans-serif;
            background: linear-gradient(135deg, #f5f7fa 0%, #e4e9f2 100%);
            color: #333;
            line-height: 1.6;
            padding: 20px;
            min-height: 100vh;
        }
        
        /* 加载动画 */
        .loader {
            display: none;
            position: fixed;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            z-index: 9999;
        }
        
        .loader.active {
            display: block;
        }
        
        .loader-spinner {
            width: 50px;
            height: 50px;
            border: 5px solid #f3f3f3;
            border-top: 5px solid #4CAF50;
            border-radius: 50%;
            animation: spin 1s linear infinite;
        }
        
        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }
        
        .container {
            max-width: 1200px;
            margin: 0 auto;
            background-color: #fff;
            border-radius: 10px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            overflow: hidden;
            animation: fadeIn 0.8s ease-in-out;
        }
        
        @keyframes fadeIn {
            from {
                opacity: 0;
                transform: translateY(20px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }
        
        header {
            background: linear-gradient(135deg, #4CAF50 0%, #45a049 100%);
            color: white;
            padding: 10px;
            text-align: center;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 1000;
        }
        
        h1 {
            font-size: 2.5em;
            margin-bottom: 10px;
        }
        
        .header {
            background-color: white;
            position: fixed;
            top: 100px;
            left: 0;
            right: 0;
            z-index: 999;
            padding: 10px 0 0 0;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
        }
        
        .book-selector {
            padding: 10px;
            background-color: #f9f9f9;
            border-bottom: 1px solid #eee;
            text-align: center;
        }
        
        .book-selector h2 {
            margin-bottom: 15px;
            color: #333;
        }
        
        .book-buttons {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 15px;
        }
        
        .book-btn {
            padding: 14px 28px;
            font-size: 16px;
            font-weight: bold;
            background-color: #4CAF50;
            color: white;
            border: none;
            border-radius: 8px;
            cursor: pointer;
            transition: all 0.3s ease;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
            /* 添加触摸反馈 */
            -webkit-tap-highlight-color: transparent;
            touch-action: manipulation;
        }
        
        .book-btn:hover {
            background-color: #45a049;
            transform: translateY(-2px);
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
        }
        
        .book-btn.active {
            background-color: #2196F3;
            transform: translateY(-1px);
            box-shadow: 0 3px 9px rgba(33, 150, 243, 0.3);
        }
        
        .content {
            padding: 30px;
            margin-top: 215px;
        }
        
        .lessons-container {
            margin-top: 20px;
        }
        
        .type-header {
            margin-top: 30px;
            margin-bottom: 20px;
            padding: 10px 15px;
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            border-left: 4px solid #4CAF50;
            border-radius: 4px;
        }

        .type-header h2 {
            margin: 0;
            color: #333;
            font-size: 24px;
            font-weight: 600;
        }
        

        
        .lesson {
            margin-bottom: 30px;
            padding: 25px;
            background-color: #fafafa;
            border-radius: 12px;
            border-left: 5px solid #4CAF50;
            transition: all 0.3s ease;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
        }
        
        .lesson:hover {
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
            transform: translateX(5px);
        }
        
        .lesson h3 {
            color: #4CAF50;
            margin-bottom: 15px;
            font-size: 1.5em;
        }
        
        .characters {
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
        }
        
        .character {
            padding: 15px 20px;
            font-size: 28px;
            font-weight: bold;
            text-align: center;
            background-color: #fff;
            border: 2px solid #e0e0e0;
            border-radius: 8px;
            cursor: pointer;
            transition: all 0.3s ease;
            min-width: 50px;
            position: relative;
            overflow: hidden;
            /* 添加触摸反馈 */
            -webkit-tap-highlight-color: transparent;
            touch-action: manipulation;
        }

        /* 重点生字样式 */
        .character.key-character {
            background-color: #ffe8c9;
            color: #d17c0b;
            font-weight: bold;
            border: 2px solid #d17c0b;
        }

        .character.key-character:hover {
            background-color: #ffd591;
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(209, 124, 11, 0.2);
        }
        
        .character:hover {
            border-color: #4CAF50;
            transform: translateY(-3px) scale(1.05);
            box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
        }
        
        .character:active {
            transform: translateY(-1px) scale(1.02);
            box-shadow: 0 3px 6px rgba(0, 0, 0, 0.1);
            /* 触摸设备上的视觉反馈 */
            background-color: #f0f9ff;
        }
        
        .character::after {
            content: '';
            position: absolute;
            top: 50%;
            left: 50%;
            width: 5px;
            height: 5px;
            background: rgba(76, 175, 80, 0.5);
            opacity: 0;
            border-radius: 100%;
            transform: scale(1, 1) translate(-50%, -50%);
            transform-origin: 50% 50%;
        }
        
        .character:focus {
            outline: none;
        }
        
        .character:focus::after {
            animation: ripple 0.5s ease-out;
        }
        
        @keyframes ripple {
            0% {
                transform: scale(0, 0);
                opacity: 0.5;
            }
            100% {
                transform: scale(100, 100);
                opacity: 0;
            }
        }
        
        .character-info-modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0, 0, 0, 0.6);
            z-index: 1000;
            justify-content: center;
            align-items: center;
            animation: fadeInBackground 0.3s ease-out;
        }
        
        @keyframes fadeInBackground {
            from {
                opacity: 0;
            }
            to {
                opacity: 1;
            }
        }
        
        .modal-content {
            background-color: white;
            border-radius: 15px;
            padding: 30px;
            max-width: 800px;
            width: 95%;
            max-height: 90vh;
            overflow-y: auto;
            box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
            animation: slideIn 0.3s ease-out;
            position: relative;
            /* 优化移动设备上的滚动体验 */
            -webkit-overflow-scrolling: touch;
            overflow-scrolling: touch;
        }
        
        @keyframes slideIn {
            from {
                opacity: 0;
                transform: translateY(-50px) scale(0.9);
            }
            to {
                opacity: 1;
                transform: translateY(0) scale(1);
            }
        }
        
        .modal-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
            padding-bottom: 15px;
            border-bottom: 2px solid #f0f0f0;
        }
        
        .modal-title {
            font-size: 24px;
            font-weight: bold;
            color: #333;
            margin: 0;
        }
        
        .close-btn {
            background: #f44336;
            color: white;
            border: none;
            padding: 12px 24px;
            border-radius: 8px;
            cursor: pointer;
            font-size: 16px;
            font-weight: bold;
            margin-top: 20px;
            transition: all 0.3s ease;
            display: inline-block;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
        }
        
        .close-btn:hover {
            background: #d32f2f;
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.25);
        }
        
        .close-btn:active {
            transform: translateY(0);
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
        }
        
        .close-icon {
            position: absolute;
            top: 15px;
            right: 15px;
            background: #f5f5f5;
            border: none;
            font-size: 24px;
            cursor: pointer;
            color: #666;
            transition: all 0.3s ease;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            /* 添加触摸反馈 */
            -webkit-tap-highlight-color: transparent;
            touch-action: manipulation;
        }
        
        .close-icon:hover {
            background-color: #f5f5f5;
            color: #333;
        }
        
        .character-iframe {
            width: 100%;
            height: 500px;
            border: none;
        }
        
        /* 平板设备样式 */
        @media (max-width: 1024px) {
            .container {
                max-width: 95%;
            }
            
            h1 {
                font-size: 2.2em;
            }
            
            .content {
                padding: 20px;
            }
        }
        
        /* 小型平板和大型手机样式 */
        @media (max-width: 768px) {
            body {
                padding: 10px;
            }
            
            h1 {
                font-size: 2em;
            }
            
            header {
                padding: 20px;
            }
            
            .book-selector {
                padding: 15px;
            }
            
            .book-buttons {
                flex-direction: column;
                align-items: center;
                gap: 10px;
            }
            
            .book-btn {
                width: 100%;
                max-width: 300px;
                padding: 12px 24px;
                font-size: 16px;
            }
            
            .content {
                padding: 15px;
            }
            
            .lesson {
                padding: 20px;
                margin-bottom: 20px;
            }
            
            .lesson h3 {
                font-size: 1.3em;
            }
            
            .character {
                font-size: 24px;
                padding: 12px 16px;
                min-width: 45px;
            }
            
            .modal-content {
                padding: 20px;
                max-width: 95%;
                margin: 10px;
            }
            
            .character-iframe {
                height: 400px;
            }
        }
        
        /* 下拉选择样式 */
        .lesson-selector {
            margin: 10px 0;
            text-align: center;
        }
        
        .lesson-select {
            background-color: #4CAF50;
            color: white;
            padding: 12px 16px;
            font-size: 16px;
            border: none;
            cursor: pointer;
            border-radius: 4px;
            min-width: 200px;
            outline: none;
            transition: background-color 0.3s;
        }
        
        .lesson-select:hover {
            background-color: #45a049;
        }
        
        .lesson-select:focus {
            background-color: #45a049;
        }
        
        .lesson-select option {
            background-color: white;
            color: #333;
            padding: 10px;
        }
        
        .lesson-select option:disabled {
            background-color: #f5f5f5;
            color: #999;
            font-weight: bold;
        }
        
        /* 平板设备样式 */
        @media (max-width: 1024px) {
            .container {
                max-width: 95%;
            }
            
            h1 {
                font-size: 2.2em;
            }
            
            .content {
                padding: 20px;
            }
        }
        
        /* 小型平板和大型手机样式 */
        @media (max-width: 768px) {
            body {
                padding: 10px;
            }
            
            h1 {
                font-size: 2em;
            }
            
            header {
                padding: 20px;
            }
            
            .book-selector {
                padding: 15px;
            }
            
            .book-buttons {
                flex-direction: column;
                align-items: center;
                gap: 10px;
            }
            
            .book-btn {
                width: 100%;
                max-width: 300px;
                padding: 12px 24px;
                font-size: 16px;
            }
            
            .content {
                padding: 15px;
            }
            
            .lesson {
                padding: 20px;
                margin-bottom: 20px;
            }
            
            .lesson h3 {
                font-size: 1.3em;
            }
            
            .character {
                font-size: 24px;
                padding: 12px 16px;
                min-width: 45px;
            }
            
            .modal-content {
                padding: 20px;
                max-width: 95%;
                margin: 10px;
            }
            
            .character-iframe {
                height: 400px;
            }
        }
        
        /* 移动设备样式 */
        @media (max-width: 480px) {
            body {
                padding: 5px;
                line-height: 1.4;
            }
            
            h1 {
                font-size: 1.8em;
            }
            
            header {
                padding: 15px 10px;
            }
            
            .book-btn {
                padding: 14px 20px;
                font-size: 16px;
                width: 100%;
                max-width: none;
            }
            
            .content {
                padding: 10px;
            }
            
            .lesson {
                padding: 15px;
                margin-bottom: 15px;
            }
            
            .lesson h3 {
                font-size: 1.2em;
                margin-bottom: 10px;
            }
            
            .characters {
                gap: 8px;
            }
            
            .character {
                font-size: 22px;
                padding: 10px 14px;
                min-width: 40px;
                border-radius: 6px;
            }
            
            .modal-content {
                padding: 15px;
                width: calc(100% - 10px);
                margin: 5px;
                max-height: 95vh;
            }
            
            .modal-title {
                font-size: 20px;
            }
            
            .character-iframe {
                height: 350px;
            }
            
            .close-btn {
                width: 100%;
                padding: 12px;
            }
            
            .close-icon {
                width: 35px;
                height: 35px;
                font-size: 20px;
            }
        }