/* ============================================
   vip3mb00329 仿北京航空航天大学官网
   主色：BUAA 蓝 #002b6d  深 #001a3d  金 #c8a96a
   class 前缀统一 bh-（Beihang）
============================================ */

:root{
    --bh-blue:#002b6d;
    --bh-blue-d:#001a3d;
    --bh-blue-l:#1a4690;
    --bh-gold:#c8a96a;
    --bh-gold-d:#a08043;
    --bh-text:#222;
    --bh-mute:#666;
    --bh-line:#e6e6e6;
    --bh-bg:#f5f6f8;
}

*,*::before,*::after{box-sizing:border-box}
html,body{margin:0;padding:0}
body{font:14px/1.7 -apple-system,"PingFang SC","Microsoft YaHei",Arial,sans-serif;color:var(--bh-text);background:#fff;-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block;border:0}
a{color:inherit;text-decoration:none;transition:color .25s}
a:hover{color:var(--bh-blue)}
ul,ol{margin:0;padding:0;list-style:none}
h1,h2,h3,h4,h5,h6{margin:0;font-weight:600}
.bh-container{max-width:1280px;margin:0 auto;padding:0 24px}

/* ========== 顶部工具条 ========== */
.bh-topbar{background:var(--bh-blue-d);color:#cfd8e8;font-size:13px;line-height:1;padding:8px 0;border-bottom:1px solid rgba(255,255,255,.08)}
.bh-topbar .bh-container{display:flex;align-items:center;justify-content:flex-end;gap:0}
.bh-tool-label{color:#9eb3cf;margin-right:14px}
.bh-topbar a{color:#cfd8e8;padding:0 14px;border-right:1px solid rgba(255,255,255,.18)}
.bh-topbar a:last-child{border-right:0}
.bh-topbar a:hover{color:#fff}
.bh-tool-en{font-weight:600;letter-spacing:1px}

/* ========== 主头部 ========== */
.bh-header{background:#fff;padding:24px 0 0;position:relative}
.bh-header .bh-container{display:flex;align-items:center;justify-content:space-between;gap:30px;padding-bottom:0}
.bh-logo{display:flex;align-items:center;gap:14px;flex-shrink:0;color:var(--bh-blue)}
.bh-logo img{width:64px;height:64px;object-fit:contain;flex-shrink:0}
.bh-brand-cn{font-size:24px;color:var(--bh-blue);letter-spacing:3px;font-weight:700;line-height:1.2}
.bh-brand-en{margin:4px 0 0;font-size:11px;color:var(--bh-blue-l);letter-spacing:2px;font-weight:500}
.bh-nav{flex:1;min-width:0}
.bh-nav ul{display:flex;justify-content:flex-end;align-items:center;gap:0;flex-wrap:nowrap}
.bh-nav li{flex:0 0 auto;padding:0;position:relative}
.bh-nav a{display:inline-block;padding:24px 14px;color:#222;font-size:15px;font-weight:600;white-space:nowrap;position:relative}
.bh-nav a::after{content:"";position:absolute;left:50%;bottom:14px;width:0;height:3px;background:var(--bh-gold);transition:width .25s,left .25s}
.bh-nav a:hover{color:var(--bh-blue)}
.bh-nav a:hover::after{left:14px;width:calc(100% - 28px)}
.bh-header-line{height:4px;background:linear-gradient(90deg,var(--bh-blue) 0,var(--bh-blue) 65%,var(--bh-gold) 100%)}

/* ========== 大轮播 Banner ========== */
.bh-banner{position:relative;background:#001a3d}
.bh-banner .swiper-container,.bh-banner .swiper-wrapper{height:480px}
.bh-banner .swiper-slide{position:relative;overflow:hidden}
.bh-banner .swiper-slide a{display:block;width:100%;height:100%;position:relative}
.bh-banner .swiper-slide img{width:100%;height:100%;object-fit:cover}
.bh-banner .bh-bn-mask{position:absolute;left:0;right:0;bottom:0;padding:60px 8% 50px;background:linear-gradient(180deg,transparent 0,rgba(0,26,61,.85) 100%);color:#fff}
.bh-banner .bh-bn-tag{display:inline-block;padding:4px 14px;background:var(--bh-gold);color:#fff;font-size:13px;letter-spacing:2px;border-radius:2px;margin-bottom:14px}
.bh-banner .bh-bn-title{font-size:32px;font-weight:700;line-height:1.4;margin:0;text-shadow:0 2px 8px rgba(0,0,0,.4)}
.bh-banner .swiper-pagination{bottom:20px!important}
.bh-banner .swiper-pagination-bullet{width:32px;height:3px;border-radius:0;background:rgba(255,255,255,.5);opacity:1;margin:0 4px!important}
.bh-banner .swiper-pagination-bullet-active{background:var(--bh-gold)}

/* ========== 通用：板块标题 ========== */
.bh-sec{padding:64px 0}
.bh-sec-head{display:flex;align-items:flex-end;justify-content:space-between;border-bottom:2px solid var(--bh-blue);padding-bottom:18px;margin-bottom:32px}
.bh-sec-head .bh-sec-title{display:flex;align-items:baseline;gap:14px}
.bh-sec-head h2{font-size:26px;color:var(--bh-blue);letter-spacing:3px;font-weight:700;line-height:1}
.bh-sec-head .bh-sec-en{font-size:13px;color:var(--bh-gold-d);letter-spacing:3px;font-weight:600}
.bh-sec-head .bh-sec-more{color:var(--bh-mute);font-size:13px;display:inline-flex;align-items:center;gap:6px}
.bh-sec-head .bh-sec-more::after{content:"›";font-size:18px;line-height:1}
.bh-sec-head .bh-sec-more:hover{color:var(--bh-blue)}

/* ========== 1. 北航新闻（左大头条 + 右日期列表） ========== */
.bh-news{background:#fff}
.bh-news-grid{display:grid;grid-template-columns:1.4fr 1fr;gap:32px;align-items:stretch}
.bh-news-feature{position:relative;overflow:hidden;border-radius:4px;background:#001a3d}
.bh-news-feature a{display:block;position:relative;height:100%;min-height:380px}
.bh-news-feature img{width:100%;height:100%;object-fit:cover;transition:transform .5s}
.bh-news-feature:hover img{transform:scale(1.04)}
.bh-news-feature .bh-nf-mask{position:absolute;left:0;right:0;bottom:0;padding:30px 28px 26px;background:linear-gradient(180deg,transparent,rgba(0,26,61,.92));color:#fff}
.bh-news-feature .bh-nf-tag{display:inline-block;padding:3px 10px;background:var(--bh-gold);font-size:12px;border-radius:2px;margin-bottom:10px}
.bh-news-feature .bh-nf-title{font-size:20px;font-weight:600;line-height:1.5;margin:0;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}

.bh-news-list{display:flex;flex-direction:column;gap:0}
.bh-news-list .bh-news-item{display:flex;align-items:center;gap:16px;padding:14px 0;border-bottom:1px dashed var(--bh-line);transition:background .25s}
.bh-news-list .bh-news-item:first-child{padding-top:0}
.bh-news-list .bh-news-item:hover{background:#fafbfd}
.bh-news-list .bh-news-thumb{flex-shrink:0;width:120px;height:74px;object-fit:cover;border-radius:3px;background:#001a3d}
.bh-news-list .bh-news-info{flex:1;min-width:0;display:flex;flex-direction:column;justify-content:center;gap:8px}
.bh-news-list .bh-news-tt{font-size:15px;color:#222;line-height:1.55;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;font-weight:500;margin:0}
.bh-news-list .bh-news-date{font-size:12px;color:var(--bh-mute)}
.bh-news-list .bh-news-item:hover .bh-news-tt{color:var(--bh-blue)}

/* ========== 2. 北航人物（4 卡片） ========== */
.bh-people{background:var(--bh-bg)}
.bh-people-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.bh-ppl-card{background:#fff;border-radius:4px;overflow:hidden;box-shadow:0 2px 8px rgba(0,26,61,.06);transition:transform .3s,box-shadow .3s;display:block}
.bh-ppl-card:hover{transform:translateY(-4px);box-shadow:0 12px 28px rgba(0,26,61,.14)}
.bh-ppl-cover{aspect-ratio:4/3;overflow:hidden;background:#001a3d;position:relative}
.bh-ppl-cover img{width:100%;height:100%;object-fit:cover;transition:transform .5s}
.bh-ppl-card:hover .bh-ppl-cover img{transform:scale(1.06)}
.bh-ppl-cover .bh-ppl-tag{position:absolute;left:0;top:14px;padding:4px 14px;background:var(--bh-blue);color:#fff;font-size:12px;letter-spacing:1px}
.bh-ppl-body{padding:18px 20px 22px}
.bh-ppl-body h3{font-size:16px;color:#222;line-height:1.55;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;min-height:50px;font-weight:600}
.bh-ppl-card:hover .bh-ppl-body h3{color:var(--bh-blue)}
.bh-ppl-body p{margin:10px 0 0;font-size:13px;color:var(--bh-mute);line-height:1.6;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}

/* ========== 3. 教学科研（左特写图 + 右列表） ========== */
.bh-research{background:#fff}
.bh-research-grid{display:grid;grid-template-columns:1.1fr 1fr;gap:32px}
.bh-rs-feature{display:block;position:relative;overflow:hidden;border-radius:4px;background:var(--bh-blue-d);min-height:340px}
.bh-rs-feature img{width:100%;height:100%;object-fit:cover;position:absolute;inset:0}
.bh-rs-feature .bh-rs-mask{position:absolute;left:0;right:0;bottom:0;padding:28px 30px;background:linear-gradient(180deg,transparent,rgba(0,26,61,.92));color:#fff;z-index:2}
.bh-rs-feature .bh-rs-cat{display:inline-block;padding:3px 10px;background:var(--bh-gold);font-size:12px;border-radius:2px;margin-bottom:8px}
.bh-rs-feature .bh-rs-title{font-size:20px;line-height:1.5;font-weight:600}
.bh-rs-list{display:flex;flex-direction:column;gap:0}
.bh-rs-item{display:flex;align-items:flex-start;gap:16px;padding:16px 0;border-bottom:1px solid var(--bh-line);transition:background .25s}
.bh-rs-item:first-child{padding-top:0}
.bh-rs-item:last-child{border-bottom:0}
.bh-rs-item:hover{background:#fafbfd}
.bh-rs-item .bh-rs-thumb{flex-shrink:0;width:140px;height:90px;object-fit:cover;border-radius:3px;background:#001a3d}
.bh-rs-item .bh-rs-info{flex:1;min-width:0;display:flex;flex-direction:column;gap:6px}
.bh-rs-item .bh-rs-cat-line{display:inline-block;align-self:flex-start;padding:2px 10px;background:#eef2f7;color:var(--bh-blue);font-size:12px;border-radius:2px;font-weight:500}
.bh-rs-item h4{font-size:15px;line-height:1.55;font-weight:600;color:#222;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;margin:0}
.bh-rs-item:hover h4{color:var(--bh-blue)}
.bh-rs-item p{font-size:12px;color:var(--bh-mute);line-height:1.55;display:-webkit-box;-webkit-line-clamp:1;-webkit-box-orient:vertical;overflow:hidden;margin:0}

/* ========== 4. 媒体北航（图文卡片网格） ========== */
.bh-media{background:var(--bh-bg)}
.bh-media-grid{display:grid;grid-template-columns:1fr;gap:0}
.bh-md-list{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.bh-md-card{display:flex;flex-direction:column;background:#fff;border-radius:4px;overflow:hidden;box-shadow:0 2px 8px rgba(0,26,61,.06);transition:transform .3s,box-shadow .3s}
.bh-md-card:hover{transform:translateY(-4px);box-shadow:0 12px 28px rgba(0,26,61,.14)}
.bh-md-thumb{display:block;width:100%;aspect-ratio:16/10;object-fit:cover;background:#001a3d}
.bh-md-body{padding:14px 16px 18px;display:flex;flex-direction:column;gap:8px}
.bh-md-cat-line{display:inline-block;align-self:flex-start;padding:2px 8px;background:#fff;color:var(--bh-blue);border:1px solid var(--bh-blue-l);font-size:11px;border-radius:2px;font-weight:500}
.bh-md-card h4{font-size:14px;color:#222;line-height:1.55;font-weight:600;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;min-height:43px;margin:0}
.bh-md-card:hover h4{color:var(--bh-blue)}
.bh-md-date{font-size:12px;color:var(--bh-mute)}

/* ========== 5. 学术文化（图文卡片 讲座/活动） ========== */
.bh-academic{background:#fff}
.bh-acad-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:24px}
.bh-acad-card{display:flex;flex-direction:column;background:#fff;border:1px solid var(--bh-line);border-radius:4px;overflow:hidden;transition:all .3s}
.bh-acad-card:hover{border-color:var(--bh-blue);transform:translateY(-3px);box-shadow:0 8px 22px rgba(0,26,61,.1)}
.bh-acad-thumb{display:block;width:100%;aspect-ratio:16/9;object-fit:cover;background:#001a3d}
.bh-acad-body{padding:18px 18px 20px;border-left:4px solid var(--bh-gold);transition:border-color .3s}
.bh-acad-card:hover .bh-acad-body{border-left-color:var(--bh-blue)}
.bh-acad-date{display:flex;align-items:baseline;gap:8px;color:var(--bh-blue);margin-bottom:10px}
.bh-acad-date .bh-ad-d{font-size:28px;font-weight:700;line-height:1}
.bh-acad-date .bh-ad-ym{font-size:13px;color:var(--bh-mute)}
.bh-acad-cat{display:inline-block;padding:2px 10px;background:var(--bh-blue);color:#fff;font-size:12px;border-radius:2px;margin-bottom:10px}
.bh-acad-card h3{font-size:14px;line-height:1.55;color:#222;font-weight:600;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;min-height:43px;margin:0}
.bh-acad-card:hover h3{color:var(--bh-blue)}
.bh-acad-place{margin:8px 0 0;font-size:12px;color:var(--bh-mute);line-height:1.55;display:-webkit-box;-webkit-line-clamp:1;-webkit-box-orient:vertical;overflow:hidden}

/* ========== 6. 数据北航（大数字统计） ========== */
.bh-facts{background:linear-gradient(135deg,var(--bh-blue) 0,var(--bh-blue-d) 100%);color:#fff;padding:72px 0;position:relative;overflow:hidden}
.bh-facts .bh-sec-head{border-bottom-color:rgba(255,255,255,.25);position:relative}
.bh-facts .bh-sec-head h2{color:#fff}
.bh-facts .bh-sec-head .bh-sec-en{color:var(--bh-gold)}
.bh-facts-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:30px 20px;position:relative}
.bh-fact{text-align:center;padding:14px 8px}
.bh-fact .bh-fact-num{font-size:48px;font-weight:700;color:var(--bh-gold);line-height:1;letter-spacing:1px;font-family:Georgia,"Times New Roman",serif}
.bh-fact .bh-fact-label{margin-top:10px;font-size:13px;color:#cfd8e8;line-height:1.5}

/* ========== 友情链接 + 页脚 ========== */
.bh-flinks{background:var(--bh-blue-d);color:#cfd8e8;padding:22px 0}
.bh-flinks .bh-container{display:flex;align-items:center;flex-wrap:wrap;row-gap:10px;line-height:1.6}
.bh-fl-label{color:var(--bh-gold);font-weight:700;font-size:15px;margin-right:18px;flex-shrink:0}
.bh-flinks ul,.bh-flinks .bh-container>li{display:inline-flex;flex-wrap:wrap;align-items:center;list-style:none!important;margin:0;padding:0;row-gap:10px}
.bh-flinks ul{display:flex}
.bh-flinks li{flex:0 0 auto;list-style:none!important;position:relative;padding-right:22px;margin-right:22px}
.bh-flinks li::marker{content:none}
.bh-flinks li::after{content:"";position:absolute;right:0;top:50%;transform:translateY(-50%);width:1px;height:14px;background:rgba(255,255,255,.25)}
.bh-flinks li:last-child,.bh-flinks .bh-container>li:last-of-type{padding-right:0;margin-right:0}
.bh-flinks li:last-child::after,.bh-flinks .bh-container>li:last-of-type::after{display:none}
.bh-flinks a{display:inline-block;color:#cfd8e8;font-size:14px;line-height:1.6;max-width:260px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;vertical-align:middle;text-decoration:none}
.bh-flinks a:hover{color:#fff}

.bh-footer{background:var(--bh-blue);color:#cfd8e8;padding:50px 0 0}
.bh-ft-grid{display:grid;grid-template-columns:280px 1fr;gap:60px;padding-bottom:36px;border-bottom:1px solid rgba(255,255,255,.12)}
.bh-ft-info p{margin:0 0 10px;font-size:14px;color:#cfd8e8;line-height:1.8}
.bh-ft-quick-title{font-size:16px;color:#fff;letter-spacing:3px;margin-bottom:18px;padding-bottom:10px;border-bottom:1px solid rgba(255,255,255,.18)}
.bh-ft-quick-grid{display:grid;grid-template-columns:repeat(7,1fr);gap:10px 18px}
.bh-ft-quick-grid a{font-size:13px;color:#cfd8e8;padding:6px 0;border-bottom:1px dashed rgba(255,255,255,.1)}
.bh-ft-quick-grid a:hover{color:var(--bh-gold)}
.bh-ft-bottom{padding:22px 0 26px;text-align:center;font-size:13px;color:#9eb3cf;line-height:1.9}
.bh-ft-bottom a{color:#cfd8e8}
.bh-ft-bottom a:hover{color:var(--bh-gold)}

/* ========== 响应式 ========== */
@media (max-width:1200px){
    .bh-brand-cn{font-size:22px;letter-spacing:2px}
    .bh-nav a{padding:24px 10px;font-size:14px}
    .bh-banner .swiper-container,.bh-banner .swiper-wrapper{height:380px}
    .bh-people-grid,.bh-acad-grid{grid-template-columns:repeat(2,1fr)}
    .bh-md-list{grid-template-columns:repeat(2,1fr)}
    .bh-media-grid{grid-template-columns:1fr;}
    .bh-facts-grid{grid-template-columns:repeat(4,1fr)}
}
@media (max-width:980px){
    .bh-topbar,.bh-header,.bh-banner,.bh-flinks,.bh-footer{display:none}
}