:root{--blue:#0B3D91;--ink:#14213d;--muted:#68758b;--line:#e6ebf2;--bg:#f6f8fc;--white:#fff;--shadow:0 16px 45px rgba(18,43,83,.1)}
    *{box-sizing:border-box}
    body{margin:0;color:var(--ink);background:var(--bg);font-family:Arial,"Microsoft YaHei","微软雅黑",sans-serif;line-height:1.6}
    a{color:inherit;text-decoration:none}
    img{max-width:100%;display:block}
    .container{width:min(1180px,calc(100% - 32px));margin:auto}
    .topbar{background:#10213f;color:#dbe5f7;font-size:13px}
    .topbar .container{min-height:36px;display:flex;align-items:center;justify-content:space-between;gap:20px}
    .topbar a{margin-left:20px;color:#fff}
    .header{position:relative;z-index:20;background:#fff;border-bottom:1px solid var(--line)}
    .header-inner{min-height:76px;display:flex;align-items:center;gap:28px}
    .logo{display:flex;align-items:center;gap:10px;flex:none;font-size:19px;font-weight:800;color:var(--blue)}
    .logo img{width:38px;height:38px;object-fit:contain}
    .main-nav{margin-left:auto}
    .nav-list{display:flex;list-style:none;padding:0;margin:0;gap:4px}
    .nav-item{position:relative}
    .nav-link{display:block;padding:25px 13px;font-size:15px;font-weight:600;white-space:nowrap}
    .nav-link:hover,.nav-link:focus{color:var(--blue)}
    .has-arrow:after{content:"⌄";font-size:12px;margin-left:6px;color:#8290a5}
    .dropdown-panel,.mega-menu{position:absolute;top:calc(100% - 1px);left:50%;transform:translateX(-50%);display:none;background:#fff;border:1px solid var(--line);border-radius:0 0 14px 14px;box-shadow:var(--shadow);padding:18px;z-index:30}
    .dropdown-panel{width:260px}
    .dropdown-panel a{display:block;padding:9px 10px;border-bottom:1px solid #f0f2f6;font-size:14px}
    .mega-menu{width:650px}
    .nav-item:hover>.mega-menu,.nav-item:focus-within>.mega-menu,.nav-item:hover>.dropdown-panel,.nav-item:focus-within>.dropdown-panel{display:block}
    .mega-menu:before,.dropdown-panel:before{content:"";position:absolute;top:-12px;left:0;right:0;height:12px}
    .mega-title{font-size:14px;font-weight:800;color:var(--blue);margin:1px 0 10px}
    .mega-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-bottom:15px}
    .mega-card{display:block;padding:10px;border:1px solid var(--line);border-radius:10px;background:#fbfcff;min-width:0}
    .mega-card:hover{border-color:#a9bee4;background:#f2f6ff}
    .mega-card img{width:34px;height:34px;object-fit:contain;margin-bottom:6px}
    .mega-card strong,.mega-card small{display:block;overflow:hidden;text-overflow:ellipsis}
    .mega-card strong{font-size:13px;white-space:nowrap}
    .mega-card small{font-size:11px;color:var(--muted);line-height:1.45;margin-top:3px}
    .mega-footer{display:block;border-top:1px solid var(--line);padding-top:12px;text-align:right;color:var(--blue);font-size:13px;font-weight:700}
    .header-btns{display:flex;align-items:center;gap:9px;white-space:nowrap}
    .member-btn,.open-btn{padding:9px 13px;border-radius:8px;font-size:13px;font-weight:700}
    .member-btn{color:var(--blue);background:#edf3ff}
    .open-btn{color:#fff;background:var(--blue)}
    .hamburger{display:none;width:40px;height:38px;border:1px solid var(--line);border-radius:8px;background:#fff;cursor:pointer;padding:8px}
    .hamburger span{display:block;height:2px;background:var(--blue);margin:4px 0;transition:.2s}
    .hamburger.active span:nth-child(1){transform:translateY(6px) rotate(45deg)}
    .hamburger.active span:nth-child(2){opacity:0}
    .hamburger.active span:nth-child(3){transform:translateY(-6px) rotate(-45deg)}
    .drawer-overlay{position:fixed;inset:0;background:rgba(8,22,46,.5);opacity:0;visibility:hidden;transition:.25s;z-index:40}
    .drawer-overlay.open{opacity:1;visibility:visible}
    .mobile-drawer{position:fixed;top:0;right:0;width:min(380px,88vw);height:100vh;background:#fff;transform:translateX(105%);transition:.3s;z-index:41;overflow:auto}
    .mobile-drawer.open{transform:translateX(0)}
    .drawer-head{display:flex;align-items:center;gap:12px;padding:20px;border-bottom:1px solid var(--line);font-weight:800;color:var(--blue)}
    .drawer-head>a{margin-left:auto;color:#fff;background:var(--blue);border-radius:6px;padding:6px 12px;font-size:13px}
    .drawer-close{border:0;background:none;font-size:28px;color:#65738a;cursor:pointer}
    .drawer-menu{padding:12px 20px 30px}
    .drawer-link,.drawer-toggle{display:block;width:100%;padding:14px 2px;border:0;border-bottom:1px solid var(--line);background:none;text-align:left;font-size:15px;color:var(--ink);cursor:pointer}
    .drawer-toggle:after{content:"＋";float:right;color:#8190a4}
    .drawer-toggle.active{color:var(--blue)}
    .drawer-toggle.active:after{content:"－"}
    .drawer-submenu{display:none;padding:5px 0 8px 15px}
    .drawer-submenu.open{display:block}
    .drawer-submenu a{display:block;padding:8px 0;color:var(--muted);font-size:14px}
    .footer{margin-top:70px;background:#101f3a;color:#d4deee}
    .footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;gap:34px;padding:48px 0 38px}
    .footer h3{margin:0 0 14px;color:#fff;font-size:15px}
    .footer p{margin:7px 0;font-size:13px;color:#aebbd0}
    .footer a{display:block;margin:8px 0;color:#b9c7dc;font-size:13px}
    .footer a:hover{color:#fff}
    .footer-brand strong{font-size:20px;color:#fff}
    .footer-bottom{padding:18px 0;border-top:1px solid rgba(255,255,255,.12);font-size:13px;color:#9eacc2}
    .video-detail-main{padding:48px 0 10px}
    .video-breadcrumb{color:var(--muted);font-size:13px;margin-bottom:22px}
    .video-breadcrumb a{color:var(--blue)}
    .video-detail-main h1{font-size:clamp(28px,4vw,46px);line-height:1.2;margin:0 0 16px;color:#10213f}
    .video-meta{display:flex;flex-wrap:wrap;gap:18px;color:var(--muted);font-size:14px;margin-bottom:28px}
    .video-stage{background:#0b1427;border-radius:18px;padding:14px;box-shadow:var(--shadow)}
    .video-cover{position:relative;aspect-ratio:16/8.2;overflow:hidden;border-radius:12px;background:#172640}
    .video-cover img{width:100%;height:100%;object-fit:cover;opacity:.78}
    .video-cover:after{content:"▶";position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);display:grid;place-items:center;width:76px;height:76px;border-radius:50%;background:rgba(255,255,255,.93);color:var(--blue);font-size:28px;padding-left:5px}
    .video-player{width:100%;min-height:420px;display:flex;align-items:center;justify-content:center;color:#dce7fa;font-size:15px}
    .video-layout{display:grid;grid-template-columns:minmax(0,1fr) 310px;gap:28px;margin-top:30px}
    .video-panel,.related-panel{background:#fff;border:1px solid var(--line);border-radius:16px;padding:25px}
    .video-panel h2,.related-panel h2{font-size:21px;margin:0 0 16px;color:#10213f}
    .video-description{color:#53627a;white-space:pre-line}
    .video-content{min-width:0;max-width:100%;overflow-x:auto;color:#34445d}
    .video-content img,.video-content table{max-width:100%}
    .video-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:24px;padding-top:18px;border-top:1px solid var(--line)}
    .video-tags a{padding:5px 10px;border-radius:20px;background:#edf3ff;color:var(--blue);font-size:12px}
    .related-card{display:grid;grid-template-columns:100px 1fr;gap:12px;padding:12px 0;border-bottom:1px solid var(--line)}
    .related-card:last-child{border-bottom:0}
    .related-card img{width:100px;height:65px;border-radius:8px;object-fit:cover}
    .related-card strong{display:block;font-size:14px;line-height:1.45}
    .related-card small{display:block;color:var(--muted);font-size:12px;margin-top:4px}
    .video-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:25px}
    .video-actions a{padding:10px 17px;border-radius:8px;background:var(--blue);color:#fff;font-size:14px;font-weight:700}
    .video-actions a.secondary{background:#edf3ff;color:var(--blue)}
    @media(max-width:1050px){
      .main-nav{display:none}.hamburger{display:block}.header-inner{justify-content:space-between}.header-btns{margin-left:auto}
      .video-layout{grid-template-columns:1fr}.related-panel{display:block}
    }
    @media(max-width:700px){
      .topbar .container{display:block;padding:8px 0}.topbar a{margin:0 14px 0 0}
      .header-inner{min-height:66px}.member-btn{display:none}.open-btn{padding:8px 10px}
      .footer-grid{grid-template-columns:1fr 1fr;gap:24px}.video-detail-main{padding-top:30px}
      .video-panel,.related-panel{padding:18px}.video-player{min-height:220px}.video-cover:after{width:58px;height:58px;font-size:22px}
    }
    @media(max-width:480px){
      .container{width:min(100% - 24px,1180px)}.footer-grid{grid-template-columns:1fr}.video-detail-main h1{font-size:29px}
      .video-meta{gap:8px 14px}.video-stage{padding:7px}.related-card{grid-template-columns:88px 1fr}.related-card img{width:88px;height:60px}
    }