* { margin: 0; padding: 0; box-sizing: border-box; font-family: "Microsoft YaHei", "微软雅黑", Arial, sans-serif; }
body { background-color: #f5f7fa; color: #333; line-height: 1.6; }
a { text-decoration: none; color: inherit; }
ul, ol { list-style: none; }
.container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 15px; }
.header { background-color: #3498db; color: white; padding: 20px 0; margin-bottom: 25px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); }
.header-content { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; }
.logo { font-size: 28px; font-weight: bold; margin-bottom: 10px; }
.logo span { font-weight: normal; opacity: 0.9; }
.nav-menu ul { display: flex; flex-wrap: wrap; }
.nav-menu li { margin-left: 20px; margin-bottom: 5px; }
.nav-menu a { color: white; font-size: 16px; padding: 5px 10px; border-radius: 4px; transition: background-color 0.3s; }
.nav-menu a:hover { background-color: rgba(255,255,255,0.2); }
.search-box { margin: 20px 0; background-color: white; padding: 20px; border-radius: 8px; box-shadow: 0 2px 8px rgba(0,0,0,0.05); }
.search-form { display: flex; position: relative; }
.search-input { flex: 1; padding: 12px 15px; border: 1px solid #ddd; border-radius: 4px; font-size: 16px; transition: all 0.3s; }
.search-input:focus { border-color: #3498db; outline: none; box-shadow: 0 0 0 3px rgba(52,152,219,0.1); }
.search-btn { position: absolute; right: 10px; top: 50%; transform: translateY(-50%); background: none; border: none; color: #3498db; cursor: pointer; font-size: 16px; }
.content { display: flex; margin-bottom: 25px; flex-wrap: wrap; }
.main { flex: 3; min-width: 0; margin-right: 20px; }
.sidebar { flex: 1; min-width: 280px; }
.card { background-color: white; margin-bottom: 20px; border-radius: 8px; box-shadow: 0 2px 8px rgba(0,0,0,0.05); overflow: hidden; }
.card-header { padding: 16px 20px; background-color: #f8fafc; border-bottom: 1px solid #eee; font-size: 18px; font-weight: bold; color: #3498db; }
.card-body { padding: 20px; }
.idiom-list { overflow: hidden; }
.idiom-list:after { content: ""; display: table; clear: both; }
.idiom-item { width: 48%; float: left; margin-right: 4%; margin-bottom: 15px; padding: 15px; background-color: #f9fbfd; border-left: 3px solid #3498db; transition: all 0.3s; border-radius: 4px; }
.idiom-item:nth-child(2n) { margin-right: 0; }
.idiom-item:hover { background-color: #f0f7ff; transform: translateY(-2px); box-shadow: 0 3px 10px rgba(0,0,0,0.1); }
.idiom-question { font-weight: bold; color: #3498db; display: inline; font-size: 16px; }
.idiom-question a { color: #3498db; transition: color 0.3s; }
.idiom-question a:hover { color: #2980b9; text-decoration: underline; }
.idiom-answer { color: #666; display: inline; font-size: 16px; }
.idiom-separator { color: #999; margin: 0 5px; display: inline; font-size: 16px; }
.category-nav { overflow: hidden; }
.category-nav:after { content: ""; display: table; clear: both; }
.category-link { display: block; float: left; width: 48%; margin-right: 4%; margin-bottom: 12px; padding: 12px; background-color: #f9fbfd; text-align: center; border-radius: 4px; transition: all 0.3s; border: 1px solid #eee; font-size: 15px; }
.category-link:nth-child(2n) { margin-right: 0; }
.category-link:hover { background-color: #3498db; color: white; border-color: #3498db; transform: translateY(-2px); }

.article { margin: 20px 0; font-size: 14px; color: #666; }
.article a { color: #3498db; }
.article a:hover { text-decoration: underline; }
.content-card { background-color: white; margin-bottom: 25px; border-radius: 8px; box-shadow: 0 2px 8px rgba(0,0,0,0.05); padding: 25px; }
.idiom-title { font-size: 28px; color: #2c3e50; margin-bottom: 15px; text-align: center; }
.idiom-content { font-size: 18px; line-height: 1.8; margin-bottom: 20px; }
.biaoti-ti { font-weight: bold; color: #3498db; font-size: 26px; }
.biaoti-di { font-weight: bold; color: #e74c3c; font-size: 26px; }
.idiom-separator { color: #999; margin: 0 10px; font-size: 26px; }

.explanation { background-color: #f8fafc; padding: 20px; border-radius: 6px; margin: 25px 0; border-left: 4px solid #3498db; }
.explanation h3 { color: #3498db; margin-bottom: 10px; font-size: 18px; }
.related-idioms { margin-top: 30px; }
.related-idioms h2 { color: #3498db; font-size: 20px; margin-bottom: 15px; border-bottom: 1px solid #eee; padding-bottom: 10px; }
.related-list { display: flex; flex-wrap: wrap; }
.related-item { width: 48%; margin-right: 4%; margin-bottom: 12px; }
.related-item:nth-child(2n) { margin-right: 0; }
.related-item a { display: block; padding: 10px; background-color: #f9fbfd; border-radius: 4px; transition: all 0.3s; color: #3498db; }
.related-item a:hover { background-color: #e3f2fd; transform: translateX(5px); }

.footer { background-color: #2c3e50; color: #bdc3c7; padding: 30px 0; text-align: center; }
.footer p { margin-bottom: 1px; font-size: 14px; }

/* 大屏幕（桌面）布局 */
@media (min-width: 992px) {
    .main { flex: 0 0 calc(75% - 20px); }
    .sidebar { flex: 0 0 25%; }
}

/* 中等屏幕（平板）布局 */
@media (max-width: 991px) and (min-width: 768px) {
    .main { flex: 0 0 calc(70% - 20px); }
    .sidebar { flex: 0 0 30%; }
    .idiom-item { width: 48%; margin-right: 4%; }
    .idiom-item:nth-child(2n) { margin-right: 0; }
    .category-link { width: 48%; margin-right: 4%; }
    .category-link:nth-child(2n) { margin-right: 0; }
}

/* 小屏幕（手机）布局 */
@media (max-width: 767px) {
    .header-content { flex-direction: column; text-align: center; }
    .logo { margin-bottom: 15px; font-size: 26px; }
    .nav-menu ul { justify-content: center; }
    .nav-menu li { margin: 0 10px; }
    
    .main, .sidebar { 
        flex: 0 0 100%; 
        margin-right: 0;
        margin-bottom: 20px;
    }
    
    /* 手机版每行显示2个分类 */
    .category-link { 
        width: 48%; 
        margin-right: 4%;
        margin-bottom: 12px;
    }
    .category-link:nth-child(2n) { 
        margin-right: 0; 
    }
    
    .idiom-item { 
        width: 100%; 
        margin-right: 0; 
    }
}

/* 超小屏幕布局 */
@media (max-width: 480px) {
    .logo { font-size: 24px; }
    .nav-menu a { font-size: 14px; padding: 5px 8px; }
    .search-input { padding: 10px 12px; font-size: 15px; }
    .card-header { padding: 14px 15px; font-size: 16px; }
    .card-body { padding: 15px; }
    .idiom-item { padding: 12px; }
}