/* ==========================================================================
   大学门户 CMS 前台样式 —— 按用户提供的清华首页截图复刻
   紫色主题 / 透明页头叠图 / 三栏新闻 / 大数字数据带
   ========================================================================== */
:root{
  --brand:#6a4bc4;          /* 主紫 */
  --brand-2:#7c5ce0;
  --brand-deep:#4f35a0;
  --brand-soft:#efeafc;
  --ink:#1f2024;
  --text:#2b2f33;
  --muted:#8a8d96;
  --line:#e9e7f0;
  --bg:#f6f5fa;
  --card:#ffffff;
  --shadow:0 8px 28px rgba(60,40,140,.10);
  --shadow-hover:0 14px 36px rgba(60,40,140,.16);
}
*{margin:0;padding:0;box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{font-family:"PingFang SC","Microsoft YaHei","Helvetica Neue",Arial,sans-serif;color:var(--text);font-size:15px;line-height:1.7;background:#fff;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none;transition:color .2s}
a:hover{color:var(--brand-2)}
img{max-width:100%;display:block;border:0}
ul,ol{list-style:none}
.container{max-width:1240px;margin:0 auto;padding:0 24px}

/* ---------- 顶部工具条 + Logo + 导航（叠在图上，左Logo 右上两栏，最右汉堡） ---------- */
.site-header{position:absolute;top:0;left:0;right:0;z-index:25;background:linear-gradient(180deg,rgba(0,0,0,.35),rgba(0,0,0,0))}
.header-inner{max-width:100%;margin:0 auto;display:flex;align-items:flex-start;justify-content:flex-start;padding:14px 30px 0;gap:16px}
.brand{display:flex;align-items:center;gap:12px;flex-shrink:0;margin-top:6px;margin-right:auto}
.brand-seal{width:54px;height:54px;border-radius:50%;background:#fff;color:var(--brand);display:flex;align-items:center;justify-content:center;font-size:19px;font-weight:700}
.brand-text strong{display:block;font-size:28px;color:#fff;font-weight:700;letter-spacing:3px;line-height:1.05;text-shadow:0 2px 10px rgba(0,0,0,.3)}
.brand-text small{display:block;color:rgba(255,255,255,.85);font-size:11px;letter-spacing:2px;margin-top:3px;text-transform:uppercase}

.header-right{display:flex;flex-direction:column;align-items:flex-end;gap:2px}
/* 顶部工具条：右对齐 */
.topbar{color:rgba(255,255,255,.9);font-size:12.5px;display:flex;align-items:center}
.topbar a{color:rgba(255,255,255,.9);padding:0 10px;line-height:1}
.topbar a:hover{color:#fff}
.topbar .sep{color:rgba(255,255,255,.4);padding:0 2px}
.topbar .icon-btn{display:inline-flex;align-items:center;justify-content:center;width:30px;height:30px;border-radius:50%;background:rgba(255,255,255,.12);color:#fff;margin-left:4px}

/* 最右紫色汉堡按钮（与工具条同高） */
.hamburger{flex-shrink:0;width:54px;height:54px;border:0;background:var(--brand);color:#fff;font-size:22px;cursor:pointer;display:flex;align-items:center;justify-content:center;border-radius:4px;margin-left:14px}

/* 主导航：右对齐，字体略小 */
.nav-bar{position:relative;margin-top:6px}
.main-nav{display:flex;flex-wrap:wrap;justify-content:flex-end}
.main-nav>li{position:relative}
.main-nav>li>a{color:#fff;padding:0 16px;height:44px;line-height:44px;font-size:16px;font-weight:600;letter-spacing:1px;text-shadow:0 1px 6px rgba(0,0,0,.3);display:block;white-space:nowrap}
.main-nav>li>a:hover{color:#fff;background:rgba(255,255,255,.12)}
.main-nav>li.active>a{color:#fff;font-weight:600}
.main-nav .caret{font-size:10px;margin-left:3px;opacity:.8}
/* 下拉子菜单 */
.main-nav .drop{display:none;position:absolute;top:100%;right:0;transform:none;background:#fff;min-width:160px;box-shadow:0 10px 30px rgba(0,0,0,.18);z-index:60;border-radius:0 0 4px 4px;padding:6px 0}
.main-nav li.has-drop:hover .drop{display:block}
.main-nav .drop li a{display:block;padding:10px 22px;color:#333;font-size:14px;letter-spacing:1px;white-space:nowrap;text-align:center}
.main-nav .drop li a:hover{background:var(--brand-soft);color:var(--brand)}

/* ---------- 全屏多栏导航面板（点汉堡） ---------- */
.mega-overlay{position:fixed;inset:0;z-index:100;background:rgba(20,16,40,.92);backdrop-filter:blur(4px);overflow-y:auto;opacity:0;visibility:hidden;transition:.3s;padding:110px 60px 60px}
.mega-overlay.open{opacity:1;visibility:visible}
.mega-cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:36px}
.mega-col .mega-title{display:block;color:#fff;font-size:20px;font-weight:700;letter-spacing:2px;margin-bottom:16px;border-bottom:1px solid rgba(255,255,255,.2);padding-bottom:10px}
.mega-col ul li{padding:5px 0}
.mega-col ul li a{color:rgba(255,255,255,.8);font-size:14.5px;line-height:1.6}
.mega-col ul li a:hover{color:#fff;padding-left:4px}
body.mega-open{overflow:hidden}
.hamburger{font-size:22px}
.hamburger.open{background:var(--brand-deep)}

/* ---------- 页内横幅（内页，需给叠层页头留位） ---------- */
.page-banner{background:linear-gradient(120deg,var(--brand-deep),var(--brand));color:#fff;padding:180px 0 40px}
.page-banner .container{display:flex;align-items:flex-end;justify-content:space-between;flex-wrap:wrap}
.page-banner h1{font-size:30px;font-weight:700;letter-spacing:3px}
.page-banner p{color:rgba(255,255,255,.85);margin-top:6px;font-size:14px}
.page-banner .crumbs{font-size:13px;color:rgba(255,255,255,.85)}
.page-banner .crumbs a{color:#fff}

/* ---------- 首页：轮播 ---------- */
.hero{position:relative;height:760px;background:#222;overflow:hidden}
.hero-slider{position:relative;height:100%}
.hero-slide{position:absolute;inset:0;opacity:0;transition:opacity .9s;display:flex;align-items:center;justify-content:center}
.hero-slide.active{opacity:1}
.hero-slide img{width:100%;height:100%;object-fit:cover;position:absolute;inset:0;z-index:0}
.hero-slide .hero-caption{position:relative;z-index:1;color:#fff;text-align:center;text-shadow:0 2px 14px rgba(0,0,0,.5);padding:0 24px}
.hero-slide .hero-caption h2{font-size:46px;font-weight:700;letter-spacing:6px;line-height:1.3}
.hero-slide .hero-caption p{margin-top:14px;font-size:17px;letter-spacing:2px}
.hero-dots{position:absolute;bottom:120px;left:50%;transform:translateX(-50%);display:flex;align-items:center;gap:10px;z-index:5}
.hero-dots span{width:10px;height:10px;border-radius:50%;background:rgba(255,255,255,.5);cursor:pointer}
.hero-dots span.active{background:#fff}
.hero-dots .more-link{color:#fff;font-size:13px;margin-left:10px;border-left:1px solid rgba(255,255,255,.4);padding-left:14px}
.hero-arrow{display:none}

/* ---------- 快速探索（斜切白卡，压在轮播底部） ---------- */
.quick-band{position:relative;z-index:10;margin-top:-90px;background:#fff;box-shadow:var(--shadow);padding:30px 40px;display:flex;align-items:center;justify-content:space-between;max-width:1240px;margin-left:auto;margin-right:auto;clip-path:polygon(2% 0,100% 0,98% 100%,0 100%)}
.quick-band .qb-title{font-size:26px;color:var(--brand);letter-spacing:2px}
.quick-band .qb-title .en{color:#c9bce8;font-size:15px;letter-spacing:1px;margin-left:10px}
.quick-band .qb-search{display:flex;align-items:center;gap:10px;color:var(--muted)}
.quick-band .qb-search input{border:0;border-bottom:1px solid var(--line);padding:8px 4px;width:260px;font-size:14px;outline:none}
.quick-band .qb-search button{border:0;background:none;font-size:20px;cursor:pointer;color:var(--brand)}

/* ---------- 区块通用 ---------- */
.section{padding:60px 0}
.section.alt{background:var(--bg)}
.sec-head{margin-bottom:30px}
.sec-head .en{display:block;color:var(--muted);font-size:13px;letter-spacing:3px;margin-bottom:6px}
.sec-head h2{font-size:30px;color:var(--ink);letter-spacing:3px;font-weight:700;display:inline-block;padding-bottom:10px;position:relative}
.sec-head h2::after{content:"";position:absolute;left:0;bottom:0;width:48px;height:4px;background:var(--brand)}
.sec-head.center{text-align:center}
.sec-head.center h2::after{left:50%;transform:translateX(-50%)}
.sec-head .more{font-size:13.5px;color:var(--muted)}
.sec-head .more:hover{color:var(--brand)}
.sec-row{display:flex;align-items:flex-end;justify-content:space-between}

/* ---------- 三栏新闻 ---------- */
.news-3col{display:grid;grid-template-columns:1fr 1.35fr 1fr;gap:36px;align-items:start}
.n3c-col .col-title{display:flex;align-items:baseline;gap:10px;margin-bottom:18px}
.n3c-col .col-title h3{font-size:18px;color:var(--ink);letter-spacing:1px}
.n3c-col .col-title .en{color:var(--muted);font-size:12px;letter-spacing:1px}
.n3c-list li{padding:13px 0;border-bottom:1px solid var(--line)}
.n3c-list li a{font-size:15px;line-height:1.5;display:block}
.n3c-list li a:hover{color:var(--brand)}
.n3c-list li time{display:block;color:var(--muted);font-size:12.5px;margin-top:3px}
/* 中栏头条轮播 */
.headline-feature{text-align:center}
.headline-feature img{width:100%;height:340px;object-fit:cover;border-radius:4px}
.hf-tag{margin:18px 0 8px;color:var(--muted);font-size:13px;letter-spacing:2px}
.hf-tag::before,.hf-tag::after{content:"——";margin:0 12px;color:var(--line)}
.headline-feature h3{font-size:22px;color:var(--ink);letter-spacing:1px;line-height:1.5;margin-bottom:12px}
.headline-feature p{color:var(--muted);font-size:14px;line-height:1.9;max-width:820px;margin:0 auto}
.hf-nav{display:flex;align-items:center;justify-content:space-between;margin-top:20px}
.hf-nav .arrow{width:44px;height:44px;border:1px solid var(--line);border-radius:50%;display:flex;align-items:center;justify-content:center;color:var(--muted);font-size:18px}
.hf-nav .arrow:hover{border-color:var(--brand);color:var(--brand)}
.hf-nav .dots{display:flex;gap:8px}
.hf-nav .dots span{width:9px;height:9px;border-radius:50%;background:#ddd}
.hf-nav .dots span.active{background:var(--brand)}

/* ---------- 三个专题大图卡 ---------- */
.promo-cards{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;margin-top:40px}
.promo-card{position:relative;border-radius:6px;overflow:hidden;height:230px;display:flex;align-items:flex-end}
.promo-card img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover}
.promo-card .pc-label{position:relative;z-index:2;color:#fff;font-size:22px;letter-spacing:2px;font-weight:700;padding:24px;text-shadow:0 2px 10px rgba(0,0,0,.5)}

/* ---------- 校园看点（横向活动） ---------- */
.events-band{background:#f3f1f9}
.events-head{display:flex;align-items:flex-end;justify-content:space-between;margin-bottom:30px}
.events-head .ev-title .en{color:var(--muted);font-size:13px;letter-spacing:3px}
.events-head .ev-title h2{font-size:30px;color:var(--ink);letter-spacing:3px;font-weight:700;display:inline-block;border-left:5px solid var(--brand);padding-left:16px;margin-left:8px}
.events-head .ev-desc{color:var(--muted);font-size:14px;flex:1;margin-left:30px;margin-bottom:8px}
.events-head .ev-more{color:var(--brand);font-size:14px;border-bottom:1px solid var(--brand);padding-bottom:2px}
.event-row{display:grid;grid-template-columns:repeat(4,1fr);gap:22px}
.event-card{background:#fff;border-radius:6px;overflow:hidden;transition:.25s}
.event-card:hover{box-shadow:var(--shadow)}
.event-card .ev-img{height:150px;overflow:hidden}
.event-card .ev-img img{width:100%;height:100%;object-fit:cover}
.event-card .ev-tag{font-size:12px;color:var(--muted);margin:12px 16px 4px}
.event-card h3{font-size:15.5px;line-height:1.5;padding:0 16px;color:var(--ink)}
.event-card:hover h3{color:var(--brand)}
.event-card .ev-meta{padding:8px 16px 16px;font-size:12.5px;color:var(--muted)}
.event-card .ev-meta .line{display:block;margin-top:4px}
.event-card .ev-meta .line::before{content:"";display:inline-block;width:6px;height:6px;border-radius:50%;background:var(--brand);margin-right:8px;vertical-align:middle}

/* ---------- 学术科研 左右分栏 ---------- */
.research-2col{display:grid;grid-template-columns:1fr 1.2fr;gap:50px;align-items:center}
.research-left .en{color:var(--muted);font-size:13px;letter-spacing:3px}
.research-left h2{font-size:30px;color:var(--ink);letter-spacing:3px;font-weight:700;margin-bottom:16px;position:relative;padding-bottom:12px}
.research-left h2::after{content:"";position:absolute;left:0;bottom:0;width:48px;height:4px;background:var(--brand)}
.research-left p{color:var(--muted);font-size:14.5px;line-height:2;margin-bottom:20px}
.research-list li{padding:14px 0;border-bottom:1px solid var(--line)}
.research-list li a{font-size:15.5px;line-height:1.5}
.research-list li a:hover{color:var(--brand)}
.research-right img{width:100%;border-radius:6px;box-shadow:var(--shadow)}

/* ---------- 数据带（紫色大数字） ---------- */
.stats-band{background:#fff;padding:70px 0;position:relative;overflow:hidden}
.stats-band::before{content:"";position:absolute;top:0;left:0;right:0;height:2px;background:var(--brand);opacity:.5}
.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:30px 20px;text-align:center}
.stat-item .num{font-size:52px;font-weight:700;color:var(--brand);line-height:1;font-family:Georgia,"Times New Roman",serif}
.stat-item .lbl{font-size:14px;color:var(--text);margin-top:10px;line-height:1.5}

/* ---------- 招生 左竖排右大图 ---------- */
.admit-2col{display:grid;grid-template-columns:1fr 1.3fr;gap:0;align-items:stretch}
.admit-list{display:flex;flex-direction:column;justify-content:center;padding:20px 40px 20px 0}
.admit-list a{display:flex;align-items:center;justify-content:space-between;padding:20px 0;border-bottom:1px solid var(--line);font-size:18px;color:var(--ink);letter-spacing:1px}
.admit-list a:hover{color:var(--brand)}
.admit-list a .arrow{color:var(--brand);font-size:20px}
.admit-img img{width:100%;height:100%;object-fit:cover;border-radius:6px;min-height:340px}

/* ---------- 社交媒体紫色区 ---------- */
.social-band{background:linear-gradient(120deg,var(--brand-deep),var(--brand));color:#fff;padding:60px 0}
.social-band .sb-head{display:flex;align-items:flex-end;justify-content:space-between;margin-bottom:30px}
.social-band .sb-head .en{color:rgba(255,255,255,.7);font-size:13px;letter-spacing:3px}
.social-band .sb-head h2{font-size:28px;letter-spacing:3px;margin-top:6px}
.social-band .sb-head .more{color:#fff;border-bottom:1px solid rgba(255,255,255,.6);padding-bottom:2px}
.social-icons{display:flex;gap:16px}
.social-icons a{width:50px;height:50px;border-radius:50%;background:rgba(255,255,255,.15);display:flex;align-items:center;justify-content:center;font-size:22px;color:#fff}
.social-icons a:hover{background:rgba(255,255,255,.3)}
.social-row{display:grid;grid-template-columns:repeat(3,1fr);gap:22px}
.social-row img{width:100%;height:200px;object-fit:cover;border-radius:6px}

/* ---------- 内页布局 ---------- */
.main-wrap{display:flex;gap:28px;padding:40px 0;min-height:420px}
.main-content{flex:1;min-width:0}
.sidebar{width:260px;flex-shrink:0}
.sidebar .side-box{border:1px solid var(--line);border-top:3px solid var(--brand);margin-bottom:18px;background:#fff}
.sidebar .side-box h3{background:var(--brand-soft);padding:12px 16px;font-size:16px;color:var(--brand);border-bottom:1px solid var(--line)}
.sidebar .side-box ul li a{display:block;padding:11px 16px;border-bottom:1px dashed #eee;color:#555;font-size:14.5px}
.sidebar .side-box ul li a:hover{color:var(--brand);background:var(--brand-soft)}

.page-layout{display:flex;gap:28px;align-items:flex-start}
.side-nav{width:230px;flex-shrink:0;border:1px solid var(--line);border-top:3px solid var(--brand);background:#fff}
.side-nav h3{background:var(--brand-soft);padding:13px 16px;color:var(--brand);font-size:16px;border-bottom:1px solid var(--line)}
.side-nav ul li a{display:block;padding:11px 16px;border-bottom:1px dashed #eee;font-size:14.5px}
.side-nav ul li a:hover{color:var(--brand);background:var(--brand-soft)}
.page-content{flex:1;min-width:0}
.block{margin-bottom:30px}
.block h2{font-size:20px;color:var(--ink);border-left:4px solid var(--brand);padding-left:12px;margin-bottom:14px;letter-spacing:1px}
.intro-para{margin:10px 0;font-size:15px;line-height:2}
.data-table{width:100%;border-collapse:collapse;font-size:14px}
.data-table th,.data-table td{border:1px solid var(--line);padding:10px 12px}
.data-table th{background:var(--brand-soft)}

/* ---------- 通用列表/卡片 ---------- */
.article-list li{padding:16px 0;border-bottom:1px solid var(--line)}
.article-list li .al-title{font-size:16.5px}
.article-list li .al-title a:hover{color:var(--brand)}
.article-list li .al-meta{color:var(--muted);font-size:12.5px;margin-top:5px}
.pagination{display:flex;gap:6px;justify-content:center;margin:24px 0}
.pagination a,.pagination span{border:1px solid var(--line);padding:6px 14px;font-size:13.5px;border-radius:3px;background:#fff}
.pagination .current{background:var(--brand);border-color:var(--brand);color:#fff}
.cat-tabs{display:flex;gap:8px;margin-bottom:18px;flex-wrap:wrap}
.cat-tabs a{border:1px solid var(--line);padding:8px 18px;border-radius:20px;font-size:14px;background:#fff}
.cat-tabs a.on{background:var(--brand);border-color:var(--brand);color:#fff}

.card-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.card-item{border:1px solid var(--line);border-radius:6px;padding:18px;background:#fff;transition:.2s}
.card-item:hover{box-shadow:var(--shadow);transform:translateY(-2px)}
.card-item .tag{color:var(--brand);font-size:12px;border:1px solid var(--brand);border-radius:3px;padding:1px 8px}
.card-item h3{font-size:16px;margin:10px 0 8px}
.card-item p{color:var(--muted);font-size:13.5px}

.btn{display:inline-block;background:var(--brand);color:#fff;border:0;padding:11px 28px;border-radius:3px;cursor:pointer;font-size:14px;letter-spacing:1px;transition:.2s}
.btn:hover{background:var(--brand-2);color:#fff}
.btn-more{display:inline-block;color:var(--brand);border:1px solid var(--brand);padding:8px 22px;border-radius:3px;font-size:14px;margin-top:14px}
.btn-more:hover{background:var(--brand);color:#fff}
.empty{padding:48px;text-align:center;color:var(--muted)}
.alert{padding:13px 16px;border-radius:4px;margin:12px 0;font-size:14px}

/* 文章页 */
.article-head h1{font-size:26px;text-align:center;padding:10px 0}
.article-meta{text-align:center;color:var(--muted);font-size:13px;padding-bottom:14px;border-bottom:1px solid var(--line);margin-bottom:18px}
.article-body{font-size:16px;line-height:2.05}
.article-body p{margin:12px 0}

/* ---------- 页脚 ---------- */
.site-footer{background:#22212b;color:#b7b6c2;font-size:13.5px}
.footer-grid{display:grid;grid-template-columns:2.2fr 1fr 1fr 1.5fr;gap:40px;padding:48px 24px 30px}
.footer-col h4{color:#fff;font-size:15px;margin-bottom:16px;letter-spacing:1px}
.footer-col ul li{padding:4px 0}
.footer-col ul li a:hover{color:#fff}
.footer-about p{margin-top:10px;line-height:1.9;color:#9a99a8}
.footer-bottom{background:#1a1922;color:#83828e;padding:16px 0;font-size:12.5px;border-top:1px solid #33323e}
.footer-bottom .container{display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px}
.footer-bottom .footer-dev{color:#b39ae0}

/* 自定义页面富文本 */
.page-custom-content{font-size:16px;line-height:2.05}
.page-custom-content h1,.page-custom-content h2,.page-custom-content h3{margin:18px 0 10px;color:var(--brand)}
.page-custom-content h1{font-size:24px}.page-custom-content h2{font-size:20px}.page-custom-content h3{font-size:17px}
.page-custom-content p{margin:12px 0}
.page-custom-content ul,.page-custom-content ol{padding-left:26px;margin:12px 0}
.page-custom-content ul{list-style:disc}
.page-custom-content img{max-width:100%;border-radius:6px;margin:12px 0}
.page-custom-content blockquote{border-left:4px solid var(--brand);background:var(--bg);padding:12px 16px;color:var(--muted);margin:12px 0}

/* ---------- 模板配色 ---------- */
body.theme-default{--brand:#6a4bc4;--brand-2:#7c5ce0;--brand-deep:#4f35a0;--brand-soft:#efeafc}
body.theme-blue{--brand:#2f5fd0;--brand-2:#4a7ae0;--brand-deep:#1e3f8c;--brand-soft:#e8eefc}
body.theme-green{--brand:#2e9e6b;--brand-2:#3fb882;--brand-deep:#1c6b48;--brand-soft:#e6f6ee}
body.theme-dark{--brand:#5a5570;--brand-2:#767090;--brand-deep:#38344c;--brand-soft:#e9e7f0}

/* ---------- 响应式 ---------- */
@media(max-width:900px){
  .site-header{position:static;background:#22212b}
  .header-inner{flex-wrap:wrap;padding:12px 16px}
  .brand-text strong{font-size:20px}
  .header-right{flex-basis:100%;align-items:stretch;order:3}
  .topbar{display:none}
  .hamburger{margin-top:0}
  .main-nav{display:none;position:static;background:var(--brand-deep);flex-direction:column;z-index:50;padding:8px 0}
  .main-nav.show{display:flex}
  .main-nav>li>a{height:44px;line-height:44px;text-align:left}
  .main-nav .drop{display:block;position:static;background:transparent;box-shadow:none;padding:0}
  .main-nav .drop li a{color:rgba(255,255,255,.85);padding:8px 24px;font-size:14px;text-align:left}
  .main-nav .drop li a:hover{background:rgba(255,255,255,.1);color:#fff}
  .hero{height:420px}
  .hero-slide .hero-caption h2{font-size:28px}
  .hero-dots{bottom:140px}
  .page-banner{padding:24px 0 30px}
  .quick-band{margin:-50px 16px 0;padding:20px}
  .news-3col{grid-template-columns:1fr;gap:30px}
  .promo-cards,.event-row,.social-row,.card-grid{grid-template-columns:1fr}
  .research-2col,.admit-2col{grid-template-columns:1fr;gap:24px}
  .stats-grid{grid-template-columns:repeat(2,1fr)}
  .main-wrap,.page-layout{flex-direction:column}
  .sidebar,.side-nav{width:100%}
  .footer-grid{grid-template-columns:1fr 1fr}
}