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

body {
    background-color: #f8f8f8;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 20px;
    background-image: linear-gradient(45deg, #FFE5E5 25%, #FFF5F5 25%, #FFF5F5 50%, #FFE5E5 50%, #FFE5E5 75%, #FFF5F5 75%, #FFF5F5 100%);
    background-size: 40px 40px;
    /* 现代系统UI字体 */
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
}

.screen {
    display: none;
    background: white;
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.1);
    min-height: 80vh;
}

.screen.active {
    display: block;
}

.title {
    text-align: center;
    color: #FF6B6B;
    font-size: 2.5em;
    margin-bottom: 40px;
    text-shadow: 2px 2px 0 #FFE5E5;
}

/* 难度选择页面 */
.difficulty-cards {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 30px;
}

.difficulty-card {
    width: 200px;
    height: 250px;
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 28px;
    color: white;
    border: none;
    transition: all 0.3s ease;
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.difficulty-card:hover {
    transform: translateY(-10px);
}

.difficulty-card[data-difficulty="睿学"] {
    background: linear-gradient(135deg, #4CAF50, #2E7D32);
}

.difficulty-card[data-difficulty="精学"] {
    background: linear-gradient(135deg, #2196F3, #0D47A1);
}

.difficulty-card[data-difficulty="好学"] {
    background: linear-gradient(135deg, #FF9800, #E65100);
}

/* 课程选择页面 */
.lesson-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    margin: 0 auto;
    max-width: 800px;
}

.lesson-btn {
    padding: 20px;
    border-radius: 15px;
    border: none;
    background: linear-gradient(135deg, #FFB6C1, #FF8DA1);
    color: white;
    font-size: 18px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(255, 182, 193, 0.3);
}

.lesson-btn:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(255, 182, 193, 0.4);
}

/* 游戏页面 */
.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding: 15px;
    background: #fff;
    border-radius: 15px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}

.score {
    font-size: 20px;
    color: #FF6B6B;
    font-weight: bold;
}

.back-button {
    padding: 10px 20px;
    border-radius: 10px;
    border: none;
    background: linear-gradient(135deg, #FF6B6B, #FF4949);
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 16px;
}

.back-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 15px rgba(255, 107, 107, 0.3);
}

/* 游戏界面容器 */
#gameScreen {
    padding: 20px; /* 减小容器内边距 */
}

/* 游戏板布局 - 确保PC端6列 */
.game-board {
    display: grid;
    grid-template-columns: repeat(6, 1fr) !important; /* 强制PC端6列 */
    gap: 10px;
    margin: 0 auto;
    padding: 5px;
    justify-content: center;
    width: 100%;
    min-height: 300px; /* 给定最小高度防止布局移动 */
}

/* 简化后的卡片样式 */
.card {
    aspect-ratio: 3/2;
    background: white;
    border-radius: 8px;
    border: 2px solid #FFB6C1;
    padding: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    font-size: 16px; /* 与"重新选择课程"按钮一致的字体大小 */
    font-weight: normal;
    line-height: 1.2;
    cursor: pointer;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
    word-break: break-word;
    overflow: hidden;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.15);
    border-color: #FF8DA1;
}

.card.selected {
    background: #FFE5E5;
    border-color: #FF8DA1;
}

.card.matched {
    animation: disappear 0.5s ease forwards;
    pointer-events: none;
}

@keyframes disappear {
    0% {
        transform: scale(1);
        opacity: 1;
    }
    100% {
        transform: scale(0);
        opacity: 0;
    }
}

.complete-message {
    display: none;
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: white;
    padding: 30px;
    border-radius: 20px;
    text-align: center;
    box-shadow: 0 10px 40px rgba(0,0,0,0.2);
    z-index: 1000;
    width: 90%;
    max-width: 400px;
}

.complete-message h2 {
    color: #FF6B6B;
    margin-bottom: 20px;
    font-size: 24px;
}

.complete-buttons {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-top: 20px;
}

.complete-buttons button {
    padding: 12px 24px;
    border: none;
    border-radius: 10px;
    background: linear-gradient(135deg, #FF6B6B, #FF4949);
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 16px;
}

.complete-buttons button:hover {
    transform: translateY(-3px);
    box-shadow: 0 4px 15px rgba(255, 107, 107, 0.3);
}

/* 响应式布局 */
@media (max-width: 1024px) {
    .game-board {
        grid-template-columns: repeat(5, 1fr) !important;
    }
    
    .card {
        font-size: 18px;
    }
}

/* 移动端强制4列 */
@media (max-width: 768px) {
    .difficulty-card {
        width: 180px;
        height: 220px;
        font-size: 24px;
    }

    .lesson-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 15px;
    }

    .game-board {
        grid-template-columns: repeat(4, 1fr) !important;
        gap: 6px;
        padding: 3px;
    }
    
    .card {
        border-width: 1.5px;
        padding: 3px;
        border-radius: 6px;
    }
}

@media (max-width: 480px) {
    .difficulty-card {
        width: 140px;
        height: 180px;
        font-size: 20px;
    }

    .lesson-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }

    .game-board {
        gap: 4px; /* 极小间距 */
        padding: 2px;
    }
    
    .card {
        border-width: 1px;
        padding: 2px;
    }

    .card[data-long-text="true"] {
        font-size: 10px;
    }
}

@media (max-width: 360px) {
    .game-board {
        grid-template-columns: repeat(4, 1fr);
        gap: 4px;
    }
    
    .card {
        font-size: 10px;
        padding: 3px;
        min-height: 25px;
    }
}

/* 移动端响应式调整 */
@media (max-width: 768px) {
    #gameScreen {
        padding: 10px; /* 手机端更小内边距 */
    }
}

/* 专门针对iOS设备增大字体 */
@supports (-webkit-touch-callout: none) {
    /* iOS设备特有CSS */
    .card {
        /* iOS上字体大一些 */
        font-size: 120% !important; 
    }
}