.english-learning {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
}

.article-section {
    margin-bottom: 40px;
    background: #ffffff;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    overflow: hidden;
}

.section-title {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 20px;
    margin: 0;
    font-size: 1.3em;
    font-weight: 800;
    font-family: 'Comic Mono', serif;
}

.original-content {
    background: #f8f9fa;
    border-radius: 8px;
    padding: 30px;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.08);

    /* 文字排版 */
    font-family: 'Georgia', serif;
    font-size: 18px;
    line-height: 1.8;
    color: #2d3436;
    text-align: justify;
    margin-bottom: 10px;
    transition: transform 0.2s ease;
}


/* 词汇高亮样式 */
.vocab-highlight {
    background-color: #e3f2fd;
    color: #1565c0;
    padding: 2px 4px;
    border-radius: 3px;
    font-weight: 600;
    border: 1px solid #bbdefb;
}

.vocabulary-section {
    padding: 25px;
    background: white;
}

.vocab-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 16px;
    margin-top: 15px;
}

.vocab-item {
    background: #f8f9fa;
    border: 1px solid #e9ecef;
    border-radius: 8px;
    padding: 16px;
    transition: all 0.3s ease;
    position: relative;
    cursor: pointer;
    min-height: 130px;
    perspective: 1000px;
}

.vocab-item:hover {
    background: #e3f2fd;
    border-color: #2196f3;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(33, 150, 243, 0.15);
}

/* 卡片翻转效果 */
.vocab-card {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

.vocab-item.flipped .vocab-card {
    transform: rotateY(180deg);
}

.vocab-front,
.vocab-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    justify-content: flex-start; 
    align-items: flex-start;
    box-sizing: border-box;
}

.vocab-back {
    transform: rotateY(180deg);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 8px;
    font-size: 18px;
    font-weight: 600;
    justify-content: center;
    align-items: center;
    text-align: center;
}

.vocab-term {
    font-weight: 700;
    color: #1565c0;
    font-size: 16px;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    width: 100%;
}

.vocab-term::before {
    content: "📚";
    margin-right: 8px;
    font-size: 14px;
}

.vocab-pos {
    position: absolute;
    top: 5px;
    right: 5px;
    background: #667eea;
    color: white;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 11px;
    font-weight: 500;
    z-index: 1;
}

.vocab-translation {
    color: #555;
    font-size: 14px;
    margin: 0;
    width: 100%;
    line-height: 1.4;
}

.vocab-section-title {
    color: #37474f;
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 15px;
    padding-bottom: 8px;
    border-bottom: 2px solid #e0e0e0;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .vocab-grid {
        grid-template-columns: 1fr;
    }

    .original-content,
    .vocabulary-section {
        padding: 20px 15px;
    }

    .section-title {
        padding: 15px;
        font-size: 1.1em;
    }
}

/* 动画效果 */
.article-section {
    animation: fadeInUp 0.6s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}