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

body {
    font-family: 'Microsoft YaHei', Arial, sans-serif;
    background: linear-gradient(135deg, #ff9a9e 0%, #fecfef 50%, #fecfef 100%);
    min-height: 100vh;
    padding: 20px;
    position: relative;
    overflow-x: hidden;
}

/* 移动端优化 */
@media (max-width: 768px) {
    body {
        padding: 10px;
        font-size: 14px;
    }
}

@media (max-width: 480px) {
    body {
        padding: 5px;
        font-size: 13px;
    }
}

/* 添加可爱的背景装饰 */
body::before {
    content: "🌟";
    position: fixed;
    top: 20px;
    left: 20px;
    font-size: 2em;
    animation: twinkle 2s infinite;
    z-index: 1;
}

body::after {
    content: "🎈";
    position: fixed;
    top: 60px;
    right: 30px;
    font-size: 1.5em;
    animation: float 3s ease-in-out infinite;
    z-index: 1;
}

@keyframes twinkle {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.2); }
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    overflow: hidden;
}

/* 移动端容器优化 */
@media (max-width: 768px) {
    .container {
        margin: 0 5px;
        border-radius: 15px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.1);
    }
}

@media (max-width: 480px) {
    .container {
        margin: 0;
        border-radius: 10px;
        box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    }
}

.header {
    background: linear-gradient(45deg, #ff6b6b, #4ecdc4, #45b7d1, #96ceb4);
    background-size: 400% 400%;
    animation: gradientShift 4s ease infinite;
    color: white;
    text-align: center;
    padding: 30px;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: "🎓 📚 ✨";
    position: absolute;
    top: 10px;
    left: 20px;
    font-size: 1.5em;
    animation: bounce 2s infinite;
}

.header::after {
    content: "🎯 🎨 🌈";
    position: absolute;
    top: 10px;
    right: 20px;
    font-size: 1.5em;
    animation: bounce 2s infinite 0.5s;
}

.header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
    animation: rainbow 3s linear infinite;
}

.header p {
    font-size: 1.2em;
    opacity: 0.9;
    animation: pulse 2s ease-in-out infinite;
}

/* 移动端标题优化 */
@media (max-width: 768px) {
    .header {
        padding: 20px 15px;
    }
    
    .header h1 {
        font-size: 1.8em;
        margin-bottom: 8px;
    }
    
    .header p {
        font-size: 1em;
    }
    
    .header::before,
    .header::after {
        font-size: 1.2em;
        top: 5px;
    }
    
    .header::before {
        left: 10px;
    }
    
    .header::after {
        right: 10px;
    }
}

@media (max-width: 480px) {
    .header {
        padding: 15px 10px;
    }
    
    .header h1 {
        font-size: 1.5em;
        margin-bottom: 5px;
    }
    
    .header p {
        font-size: 0.9em;
    }
    
    .header::before,
    .header::after {
        font-size: 1em;
        top: 3px;
    }
    
    .header::before {
        left: 5px;
    }
    
    .header::after {
        right: 5px;
    }
}

@keyframes gradientShift {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0); }
    40% { transform: translateY(-10px); }
    60% { transform: translateY(-5px); }
}

@keyframes rainbow {
    0% { color: #ff6b6b; }
    25% { color: #4ecdc4; }
    50% { color: #45b7d1; }
    75% { color: #96ceb4; }
    100% { color: #ff6b6b; }
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.nav {
    background: #f8f9fa;
    padding: 15px;
    border-bottom: 3px solid #e9ecef;
}

.nav ul {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: center;
}

/* 移动端导航优化 */
@media (max-width: 768px) {
    .nav {
        padding: 10px;
    }
    
    .nav ul {
        gap: 8px;
    }
}

@media (max-width: 480px) {
    .nav {
        padding: 8px;
    }
    
    .nav ul {
        flex-direction: column;
        align-items: center;
        gap: 6px;
    }
}

.nav li {
    background: white;
    border: 2px solid #dee2e6;
    border-radius: 25px;
    padding: 8px 16px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
    position: relative;
    overflow: hidden;
}

/* 移动端导航项优化 */
@media (max-width: 768px) {
    .nav li {
        padding: 6px 12px;
        font-size: 0.9em;
        min-width: 80px;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .nav li {
        padding: 8px 16px;
        font-size: 0.9em;
        width: 100%;
        max-width: 200px;
        text-align: center;
    }
}

.nav li::before {
    content: "📖";
    position: absolute;
    left: -20px;
    top: 50%;
    transform: translateY(-50%);
    opacity: 0;
    transition: all 0.3s ease;
}

.nav li:hover::before {
    left: 5px;
    opacity: 1;
}

.nav li:hover, .nav li.active {
    background: linear-gradient(45deg, #ff6b6b, #4ecdc4);
    color: white;
    border-color: #ff6b6b;
    transform: translateY(-3px) scale(1.05);
    box-shadow: 0 8px 20px rgba(0,0,0,0.2);
}

.nav li.active::after {
    content: "✨";
    position: absolute;
    right: 5px;
    top: 50%;
    transform: translateY(-50%);
    animation: sparkle 1s infinite;
}

@keyframes sparkle {
    0%, 100% { opacity: 1; transform: translateY(-50%) scale(1); }
    50% { opacity: 0.7; transform: translateY(-50%) scale(1.2); }
}

.nav-extra {
    text-align: center;
    margin-top: 15px;
}

/* 移动端额外导航优化 */
@media (max-width: 768px) {
    .nav-extra {
        margin-top: 10px;
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: 8px;
    }
    
    .nav-extra button {
        font-size: 0.8em !important;
        padding: 8px 12px !important;
        margin: 0 !important;
    }
}

@media (max-width: 480px) {
    .nav-extra {
        flex-direction: column;
        align-items: center;
        gap: 6px;
    }
    
    .nav-extra button {
        font-size: 0.8em !important;
        padding: 8px 16px !important;
        width: 100%;
        max-width: 200px;
    }
}

.rules-summary-btn {
    background: linear-gradient(45deg, #28a745, #20c997);
    color: white;
    border: none;
    border-radius: 25px;
    padding: 10px 20px;
    font-size: 1em;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
}

.rules-summary-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

.pdf-btn, .pdf-download-btn, .pdf-open-btn, .pdf-folder-btn {
    background: linear-gradient(45deg, #17a2b8, #20c997);
    color: white;
    border: none;
    border-radius: 25px;
    padding: 10px 20px;
    font-size: 1em;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
}

.pdf-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #138496, #1ea085);
}

.pdf-download-btn {
    background: linear-gradient(45deg, #fd7e14, #e83e8c);
}

.pdf-download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #e8690b, #d63384);
}

.pdf-open-btn {
    background: linear-gradient(45deg, #28a745, #20c997);
}

.pdf-open-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #218838, #1ea085);
}

.pdf-folder-btn {
    background: linear-gradient(45deg, #6f42c1, #e83e8c);
}

.pdf-folder-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #5a32a3, #d63384);
}

.image-review-btn {
    background: linear-gradient(45deg, #fd7e14, #e83e8c);
}
.image-review-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #e8690b, #d63384);
}

.phonics-web-btn {
    background: linear-gradient(45deg, #28a745, #20c997);
}
.phonics-web-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #218838, #1ea085);
}

.rules-summary {
    display: none;
    animation: fadeIn 0.5s ease;
}

.rules-summary.active {
    display: block;
}

.rules-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.rule-category {
    background: white;
    border: 2px solid #e9ecef;
    border-radius: 15px;
    padding: 20px;
    transition: all 0.3s ease;
}

.rule-category:hover {
    border-color: #007bff;
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
}

.rule-category h3 {
    color: #007bff;
    margin-bottom: 15px;
    text-align: center;
    font-size: 1.3em;
}

.rule-item {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 12px;
    margin: 8px 0;
    border-left: 4px solid #007bff;
}

.rule-pattern {
    font-weight: bold;
    color: #333;
    font-size: 1.1em;
    margin-bottom: 5px;
}

.rule-description {
    color: #666;
    font-size: 0.9em;
    line-height: 1.4;
}

.content {
    padding: 30px;
}

/* 移动端内容区域优化 */
@media (max-width: 768px) {
    .content {
        padding: 20px 15px;
    }
}

@media (max-width: 480px) {
    .content {
        padding: 15px 10px;
    }
}

.lesson {
    display: none;
    animation: fadeIn 0.5s ease;
}

.lesson.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.lesson-title {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
    font-size: 2.2em;
    background: linear-gradient(45deg, #ff6b6b, #4ecdc4, #45b7d1, #96ceb4);
    background-size: 300% 300%;
    animation: titleGradient 4s ease infinite;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    position: relative;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.1);
}

/* 移动端课程标题优化 */
@media (max-width: 768px) {
    .lesson-title {
        font-size: 1.8em;
        margin-bottom: 20px;
    }
    
    .lesson-title::before,
    .lesson-title::after {
        font-size: 0.6em;
    }
    
    .lesson-title::before {
        left: -30px;
    }
    
    .lesson-title::after {
        right: -30px;
    }
}

@media (max-width: 480px) {
    .lesson-title {
        font-size: 1.4em;
        margin-bottom: 15px;
    }
    
    .lesson-title::before,
    .lesson-title::after {
        font-size: 0.5em;
    }
    
    .lesson-title::before {
        left: -25px;
    }
    
    .lesson-title::after {
        right: -25px;
    }
}

.lesson-title::before {
    content: "🎓";
    position: absolute;
    left: -40px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.8em;
    animation: bounce 2s infinite;
}

.lesson-title::after {
    content: "✨";
    position: absolute;
    right: -40px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.8em;
    animation: bounce 2s infinite 0.5s;
}

@keyframes titleGradient {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.rules-section {
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 30px;
    border-left: 5px solid #007bff;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.rules-section h3 {
    color: #007bff;
    margin-bottom: 20px;
    font-size: 1.1em;
    text-align: center;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.1);
}

.rules-list {
    list-style: none;
}

.rules-list li {
    padding: 12px 0;
    border-bottom: 1px solid #dee2e6;
    display: flex;
    align-items: center;
    font-size: 1.1em;
    line-height: 1.6;
}

.rules-list li:last-child {
    border-bottom: none;
}

.rules-list li::before {
    content: "🎯";
    margin-right: 15px;
    font-size: 1.3em;
    animation: rotate 3s linear infinite;
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.phonetic-pattern {
    background: linear-gradient(45deg, #ff6b6b, #4ecdc4);
    color: white;
    padding: 15px;
    border-radius: 10px;
    margin: 15px 0;
    text-align: center;
    font-size: 1.2em;
    font-weight: bold;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

.pattern-examples {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin: 20px 0;
}

/* 移动端模式示例优化 */
@media (max-width: 768px) {
    .pattern-examples {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
        gap: 10px;
        margin: 15px 0;
    }
}

@media (max-width: 480px) {
    .pattern-examples {
        grid-template-columns: 1fr;
        gap: 8px;
        margin: 10px 0;
    }
}

.pattern-card {
    background: white;
    border: 2px solid #e9ecef;
    border-radius: 10px;
    padding: 15px;
    text-align: center;
    transition: all 0.3s ease;
}

.pattern-card:hover {
    border-color: #007bff;
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.pattern-letter {
    font-size: 2em;
    font-weight: bold;
    color: #007bff;
    margin-bottom: 10px;
}

.pattern-sound {
    font-size: 1.1em;
    color: #666;
    font-family: 'Arial', sans-serif;
    margin-bottom: 8px;
}

.pattern-rule {
    font-size: 0.9em;
    color: #333;
    line-height: 1.4;
}

.mouth-position {
    background: #fff3cd;
    border: 2px solid #ffeaa7;
    border-radius: 10px;
    padding: 15px;
    margin: 15px 0;
}

.mouth-position h4 {
    color: #856404;
    margin-bottom: 10px;
    font-size: 0.95em;
}

.mouth-position p {
    color: #856404;
    margin: 5px 0;
    font-size: 0.9em;
}

.play-pronunciation-btn {
    background: linear-gradient(45deg, #6f42c1, #e83e8c);
    color: white;
    border: none;
    border-radius: 20px;
    padding: 6px 12px;
    font-size: 0.8em;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
    margin-top: 8px;
    display: inline-flex;
    align-items: center;
    gap: 4px;
}

.play-pronunciation-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #5a32a3, #d63384);
}

.play-pronunciation-btn:active {
    transform: translateY(0);
}

.play-example-btn {
    background: linear-gradient(45deg, #17a2b8, #20c997);
    color: white;
    border: none;
    border-radius: 15px;
    padding: 4px 8px;
    font-size: 0.7em;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
    margin-top: 6px;
    display: inline-flex;
    align-items: center;
    gap: 3px;
}

.play-example-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 3px 10px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #138496, #1ea085);
}

.play-example-btn:active {
    transform: translateY(0);
}

.play-comparison-btn {
    background: linear-gradient(45deg, #fd7e14, #e83e8c);
    color: white;
    border: none;
    border-radius: 12px;
    padding: 3px 6px;
    font-size: 0.65em;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
    margin-top: 4px;
    display: inline-flex;
    align-items: center;
    gap: 2px;
}

.play-comparison-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 3px 8px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #e8690b, #d63384);
}

.play-comparison-btn:active {
    transform: translateY(0);
}

.play-rule-example-btn {
    background: linear-gradient(45deg, #28a745, #20c997);
    color: white;
    border: none;
    border-radius: 10px;
    padding: 2px 6px;
    font-size: 0.75em;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
    margin: 0 2px;
    display: inline-block;
}

.play-rule-example-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 2px 6px rgba(0,0,0,0.2);
    background: linear-gradient(45deg, #218838, #1ea085);
}

.play-rule-example-btn:active {
    transform: translateY(0);
}

.comparison-table {
    background: white;
    border-radius: 10px;
    padding: 20px;
    margin: 20px 0;
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
}

.comparison-table h4 {
    color: #007bff;
    margin-bottom: 15px;
    text-align: center;
}

.comparison-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin: 10px 0;
    padding: 10px;
    border-bottom: 1px solid #e9ecef;
}

.comparison-row:last-child {
    border-bottom: none;
}

.comparison-item {
    text-align: center;
    padding: 10px;
    border-radius: 8px;
    background: #f8f9fa;
}

.comparison-word {
    font-size: 1.3em;
    font-weight: bold;
    color: #333;
    margin-bottom: 5px;
}

.comparison-phonetic {
    font-size: 1em;
    color: #666;
    font-family: 'Arial', sans-serif;
}

.words-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 15px;
    margin-top: 20px;
}

/* 移动端单词网格优化 */
@media (max-width: 768px) {
    .words-grid {
        grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
        gap: 10px;
        margin-top: 15px;
    }
}

@media (max-width: 480px) {
    .words-grid {
        grid-template-columns: 1fr 1fr;
        gap: 8px;
        margin-top: 10px;
    }
}

.word-card {
    background: white;
    border: 2px solid #e9ecef;
    border-radius: 15px;
    padding: 12px;
    transition: all 0.4s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
}

.word-card::before {
    content: "🎯";
    position: absolute;
    top: -10px;
    right: -10px;
    font-size: 1.5em;
    opacity: 0;
    transition: all 0.3s ease;
    transform: rotate(15deg);
}

.word-card:hover::before {
    opacity: 1;
    transform: rotate(0deg);
}

.word-card:hover {
    transform: translateY(-3px) scale(1.01);
    box-shadow: 0 8px 20px rgba(0,0,0,0.15);
    border-color: #ff6b6b;
    background: linear-gradient(135deg, #fff 0%, #f8f9fa 100%);
}

.word-card::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(45deg, #ff6b6b, #4ecdc4, #45b7d1);
    background-size: 200% 200%;
    animation: gradientMove 3s ease infinite;
}

@keyframes gradientMove {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.word-english {
    font-size: 1.4em;
    font-weight: bold;
    color: #333;
    margin-bottom: 8px;
    text-align: center;
}

.word-syllables {
    font-size: 1.1em;
    color: #28a745;
    margin-bottom: 6px;
    text-align: center;
    font-weight: bold;
}

.syllable {
    display: inline-block;
    padding: 2px 4px;
    margin: 0 2px;
    border-radius: 4px;
    background: #e8f5e8;
    border: 1px solid #28a745;
    transition: all 0.2s ease;
}

.syllable:hover {
    background: #d4edda;
    transform: scale(1.05);
}

/* 音节结构颜色编码 */
.syllable-vowel {
    background: #ffeb3b;
    border-color: #f57f17;
    color: #d84315;
    font-weight: bold;
}

.syllable-consonant {
    background: #e3f2fd;
    border-color: #1976d2;
    color: #1565c0;
}

.syllable-stress {
    background: #ffcdd2;
    border-color: #d32f2f;
    color: #c62828;
    font-weight: bold;
}

.syllable-magic-e {
    background: #f3e5f5;
    border-color: #7b1fa2;
    color: #6a1b9a;
    font-style: italic;
}

/* 音标颜色编码 */
.phonetic-vowel {
    color: #ff6f00;
    font-weight: bold;
}

.phonetic-consonant {
    color: #1565c0;
}

.phonetic-stress {
    color: #d32f2f;
    font-weight: bold;
}

.phonetic-long {
    color: #2e7d32;
    font-weight: bold;
}

.phonetic-short {
    color: #f57c00;
}

.phonetic-diphthong {
    color: #7b1fa2;
    font-weight: bold;
}

.phonetic-schwa {
    color: #757575;
    font-style: italic;
}

.syllable-info {
    background: #f8f9fa;
    border-radius: 6px;
    padding: 6px;
    margin: 6px 0;
    border-left: 2px solid #28a745;
}

.syllable-info h4 {
    color: #28a745;
    margin-bottom: 4px;
    font-size: 0.9em;
}

.syllable-rule {
    font-size: 0.8em;
    color: #666;
    line-height: 1.3;
}

/* 颜色图例 */
.color-legend {
    background: white;
    border-radius: 10px;
    padding: 15px;
    margin: 15px 0;
    border: 2px solid #e9ecef;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.color-legend h4 {
    color: #333;
    margin-bottom: 10px;
    text-align: center;
}

.legend-item {
    display: inline-block;
    margin: 5px 10px;
    padding: 5px 10px;
    border-radius: 5px;
    font-size: 0.9em;
}

.legend-vowel {
    background: #ffeb3b;
    color: #d84315;
}

.legend-consonant {
    background: #e3f2fd;
    color: #1565c0;
}

.legend-stress {
    background: #ffcdd2;
    color: #c62828;
}

.legend-magic-e {
    background: #f3e5f5;
    color: #6a1b9a;
}

.word-phonetic {
    font-size: 0.95em;
    color: #666;
    margin-bottom: 6px;
    text-align: center;
    font-family: 'Arial', sans-serif;
}

.word-chinese {
    font-size: 1em;
    color: #007bff;
    text-align: center;
    margin-bottom: 10px;
}

.play-button {
    background: linear-gradient(45deg, #ff6b6b, #4ecdc4, #45b7d1);
    background-size: 200% 200%;
    animation: buttonGradient 3s ease infinite;
    color: white;
    border: none;
    border-radius: 20px;
    padding: 8px 15px;
    font-size: 0.9em;
    cursor: pointer;
    transition: all 0.3s ease;
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    font-weight: bold;
    position: relative;
    overflow: hidden;
}

.play-button::before {
    content: "🎵";
    position: absolute;
    left: -20px;
    top: 50%;
    transform: translateY(-50%);
    opacity: 0;
    transition: all 0.3s ease;
}

.play-button:hover::before {
    left: 10px;
    opacity: 1;
}

.play-button:hover {
    transform: scale(1.08) translateY(-2px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.3);
    background-size: 100% 100%;
}

.play-button:active {
    transform: scale(0.95);
}

@keyframes buttonGradient {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

/* 添加更多可爱的动画效果 */
.word-english {
    /* 移除动画以保持简洁 */
}

@keyframes wordGlow {
    from { text-shadow: 0 0 5px rgba(255, 107, 107, 0.5); }
    to { text-shadow: 0 0 15px rgba(78, 205, 196, 0.8); }
}

.word-syllables {
    /* 移除动画以保持简洁 */
}

@keyframes syllableBounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-3px); }
}

/* 添加进度条动画 */
.progress-bar {
    width: 100%;
    height: 6px;
    background: #e9ecef;
    border-radius: 3px;
    overflow: hidden;
    margin: 20px 0;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(45deg, #ff6b6b, #4ecdc4, #45b7d1);
    background-size: 200% 200%;
    animation: progressGradient 3s ease infinite;
    border-radius: 3px;
    transition: width 0.5s ease;
}

@keyframes progressGradient {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.footer {
    background: #333;
    color: white;
    text-align: center;
    padding: 20px;
    margin-top: 30px;
}

/* 移动端底部页脚优化 */
@media (max-width: 768px) {
    .footer {
        padding: 15px;
        font-size: 0.9em;
    }
}

@media (max-width: 480px) {
    .footer {
        padding: 10px;
        font-size: 0.8em;
    }
    
    .footer div {
        margin-top: 8px !important;
        font-size: 0.8em !important;
    }
}

/* 移动端触摸优化 */
@media (hover: none) and (pointer: coarse) {
    .word-card:hover {
        transform: none;
        box-shadow: 0 3px 10px rgba(0,0,0,0.1);
    }
    
    .nav li:hover {
        transform: none;
    }
    
    .pattern-card:hover {
        transform: none;
    }
    
    .play-button:hover {
        transform: none;
    }
    
    /* 增加按钮点击区域 */
    .play-button,
    .play-pronunciation-btn,
    .play-example-btn,
    .play-comparison-btn,
    .play-rule-example-btn {
        min-height: 44px;
        min-width: 44px;
        display: flex;
        align-items: center;
        justify-content: center;
    }
}

.syllable-c { color: #1976d2; font-weight: bold; }
.syllable-v { color: #ff6f00; font-weight: bold; }
.syllable-e { color: #7b1fa2; font-style: italic; }
.syllable-stress { color: #d32f2f; font-weight: bold; }
.phonetic-vowel { color: #ff6f00; font-weight: bold; }
.phonetic-consonant { color: #1565c0; }
.phonetic-stress { color: #d32f2f; font-weight: bold; }
.legend-item { display: inline-block; margin: 5px 10px; padding: 5px 10px; border-radius: 5px; font-size: 0.9em; }
.legend-vowel { background: #ffeb3b; color: #d84315; }
.legend-consonant { background: #e3f2fd; color: #1565c0; }
.legend-stress { background: #ffcdd2; color: #c62828; }
.legend-magic-e { background: #f3e5f5; color: #6a1b9a; } 

.english-vowel {
    color: #ff6f00;
    font-weight: bold;
    text-shadow: 0 1px 4px #ffe0b2;
}
.english-consonant {
    color: #1976d2;
    font-weight: bold;
    text-shadow: 0 1px 4px #bbdefb;
}

/* 移动端滚动优化 */
@media (max-width: 768px) {
    body {
        -webkit-overflow-scrolling: touch;
        scroll-behavior: smooth;
    }
    
    .container {
        -webkit-overflow-scrolling: touch;
    }
}

/* 移动端性能优化 */
@media (max-width: 768px) {
    /* 减少动画复杂度以提升性能 */
    .header {
        animation: none;
        background: linear-gradient(45deg, #ff6b6b, #4ecdc4);
    }
    
    .lesson-title {
        animation: none;
        background: linear-gradient(45deg, #ff6b6b, #4ecdc4);
        -webkit-background-clip: text;
        -webkit-text-fill-color: transparent;
        background-clip: text;
    }
    
    .play-button {
        animation: none;
        background: linear-gradient(45deg, #ff6b6b, #4ecdc4);
    }
    
    /* 简化装饰元素 */
    body::before,
    body::after {
        display: none;
    }
}

/* 移动端可访问性优化 */
@media (max-width: 768px) {
    /* 增强对比度 */
    .word-card {
        border-width: 3px;
    }
    
    .nav li {
        border-width: 3px;
    }
    
    /* 增大字体以提升可读性 */
    .word-english {
        font-size: 1.5em;
    }
    
    .word-chinese {
        font-size: 1.1em;
    }
    
    .word-phonetic {
        font-size: 1em;
    }
}

/* 横屏模式优化 */
@media (max-width: 768px) and (orientation: landscape) {
    .header {
        padding: 15px;
    }
    
    .header h1 {
        font-size: 1.6em;
        margin-bottom: 5px;
    }
    
    .header p {
        font-size: 0.9em;
    }
    
    .nav {
        padding: 8px;
    }
    
    .content {
        padding: 15px 10px;
    }
}

/* 极小屏幕优化 */
@media (max-width: 320px) {
    .words-grid {
        grid-template-columns: 1fr;
    }
    
    .pattern-examples {
        grid-template-columns: 1fr;
    }
    
    .nav ul {
        flex-direction: column;
    }
    
    .nav li {
        width: 100%;
        text-align: center;
    }
}