:root{
      --primary:#0B3D91;
      --ink:#172033;
      --muted:#667085;
      --line:#e5e9f0;
      --soft:#f4f7fb;
      --white:#fff;
      --shadow:0 16px 42px rgba(20,38,72,.10);
      --radius:16px;
    }
    *{box-sizing:border-box}
    html{scroll-behavior:smooth}
    body{margin:0;color:var(--ink);background:#fff;font-family:"Microsoft YaHei","PingFang SC",Arial,sans-serif;line-height:1.7}
    a{color:inherit;text-decoration:none}
    img{max-width:100%;display:block}
    button{font:inherit}
    .container{width:min(1180px,calc(100% - 40px));margin:0 auto}
    .topbar{background:#10213f;color:#dce6f7;font-size:13px}
    .topbar .container{min-height:36px;display:flex;align-items:center;justify-content:space-between;gap:20px}
    .topbar a{color:#dce6f7;margin-left:20px}
    .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;min-width:170px;font-size:19px;font-weight:800;color:var(--primary)}
    .logo img{width:34px;height:34px;object-fit:contain}
    .main-nav{flex:1}
    .nav-list{list-style:none;margin:0;padding:0;display:flex;justify-content:center;align-items:stretch;gap:4px}
    .nav-item{position:relative}
    .nav-link{display:flex;align-items:center;gap:6px;padding:25px 14px;color:#27344c;font-size:14px;white-space:nowrap}
    .nav-link:hover,.nav-link:focus-visible{color:var(--primary)}
    .has-arrow:after{content:"";width:6px;height:6px;border-right:1px solid currentColor;border-bottom:1px solid currentColor;transform:rotate(45deg) translateY(-2px)}
    .dropdown-panel,.mega-menu{position:absolute;top:100%;left:50%;transform:translateX(-50%) translateY(8px);width:290px;padding:20px;background:#fff;border:1px solid var(--line);border-radius:0 0 14px 14px;box-shadow:var(--shadow);opacity:0;visibility:hidden;transition:.2s;z-index:30}
    .mega-menu{width:590px}
    .nav-item:after{content:"";position:absolute;left:0;right:0;top:100%;height:12px}
    .nav-item:hover .dropdown-panel,.nav-item:focus-within .dropdown-panel,.nav-item:hover .mega-menu,.nav-item:focus-within .mega-menu{opacity:1;visibility:visible;transform:translateX(-50%) translateY(0)}
    .drop-title,.mega-title{font-weight:800;color:var(--primary);margin:0 0 12px}
    .drop-link{display:block;padding:8px 0;color:#394760;font-size:14px;border-bottom:1px solid #f0f2f6}
    .drop-link:hover{color:var(--primary)}
    .drop-link small{display:block;color:var(--muted);font-size:12px}
    .mega-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}
    .mega-card{display:flex;gap:9px;padding:10px;border:1px solid #edf0f5;border-radius:10px;background:#fbfcfe}
    .mega-card:hover{border-color:#b9cbe9;background:#f4f8ff}
    .mega-card img{width:34px;height:34px;object-fit:contain;flex:0 0 auto}
    .mega-card strong,.mega-card small{display:block}
    .mega-card strong{font-size:13px}
    .mega-card small{font-size:11px;color:var(--muted);line-height:1.45}
    .mega-footer{display:block;margin-top:15px;padding-top:12px;border-top:1px solid var(--line);font-size:13px;color:var(--primary);font-weight:700}
    .header-btns{display:flex;align-items:center;gap:10px}
    .member-btn,.open-btn{padding:8px 13px;border-radius:7px;font-size:13px;white-space:nowrap}
    .member-btn{color:var(--primary);border:1px solid #c9d7ed}
    .open-btn{background:var(--primary);color:#fff}
    .hamburger{display:none;width:40px;height:40px;border:1px solid var(--line);border-radius:8px;background:#fff;padding:9px;cursor:pointer}
    .hamburger span{display:block;height:2px;background:var(--primary);margin:5px 0;transition:.2s}
    .hamburger.active span:nth-child(1){transform:translateY(7px) rotate(45deg)}
    .hamburger.active span:nth-child(2){opacity:0}
    .hamburger.active span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}
    .drawer-overlay{position:fixed;inset:0;background:rgba(9,22,45,.48);opacity:0;visibility:hidden;transition:.2s;z-index:50}
    .drawer-overlay.open{opacity:1;visibility:visible}
    .mobile-drawer{position:fixed;top:0;right:0;width:min(390px,88vw);height:100vh;background:#fff;z-index:60;transform:translateX(100%);transition:.25s;overflow:auto;box-shadow:-12px 0 30px rgba(0,0,0,.15)}
    .mobile-drawer.open{transform:translateX(0)}
    .drawer-head{height:70px;padding:0 20px;display:flex;align-items:center;gap:12px;border-bottom:1px solid var(--line);font-weight:800}
    .drawer-head>a{margin-left:auto;color:var(--primary);font-size:14px}
    .drawer-close{border:0;background:transparent;font-size:28px;color:#667085;cursor:pointer}
    .drawer-menu{padding:12px 20px 35px}
    .drawer-link,.drawer-toggle{display:block;width:100%;padding:13px 0;border:0;border-bottom:1px solid #edf0f4;background:transparent;text-align:left;color:#27344c;cursor:pointer}
    .drawer-toggle:after{content:"+";float:right;color:var(--primary);font-size:18px}
    .drawer-toggle.active:after{content:"−"}
    .drawer-submenu{display:none;padding:4px 0 8px 15px}
    .drawer-submenu.open{display:block}
    .drawer-submenu a{display:block;padding:8px 0;color:var(--muted);font-size:13px}
    .video-detail-main{padding:52px 0 80px;background:linear-gradient(180deg,#f6f8fc 0,#fff 48%)}
    .video-detail-main .breadcrumb{font-size:13px;color:var(--muted);margin-bottom:22px}
    .video-detail-main .breadcrumb a{color:var(--primary)}
    .video-layout{display:grid;grid-template-columns:minmax(0,1fr) 310px;gap:28px;align-items:start}
    .video-primary,.video-aside{background:#fff;border:1px solid var(--line);border-radius:var(--radius);box-shadow:0 10px 28px rgba(28,48,85,.06)}
    .video-primary{padding:28px}
    .video-heading{margin-bottom:20px}
    .video-heading h1{font-size:clamp(26px,3vw,40px);line-height:1.25;margin:0 0 12px;color:#17233b}
    .video-meta{display:flex;flex-wrap:wrap;gap:10px 22px;color:var(--muted);font-size:13px}
    .video-cover{position:relative;background:#0d1b32;border-radius:12px;overflow:hidden;min-height:300px;margin:20px 0 25px;display:flex;align-items:center;justify-content:center}
    .video-cover img{width:100%;height:auto;max-height:560px;object-fit:cover;opacity:.9}
    .video-cover .player-layer{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;background:linear-gradient(180deg,transparent,rgba(3,13,31,.42))}
    .video-cover .play-mark{width:66px;height:66px;border-radius:50%;display:grid;place-items:center;background:#fff;color:var(--primary);font-size:25px;padding-left:4px;box-shadow:0 8px 25px rgba(0,0,0,.2)}
    .video-player{margin:0 0 25px;min-width:0;max-width:100%;overflow-x:auto}
    .video-player iframe,.video-player video{max-width:100%;width:100%;min-height:360px;border:0;border-radius:10px}
    .video-summary{padding:18px 20px;background:#f5f8fd;border-left:4px solid var(--primary);border-radius:8px;margin:20px 0;color:#43526a}
    .video-content{min-width:0;max-width:100%;overflow-x:auto;color:#3d4b61}
    .video-content img,.video-content table{max-width:100%}
    .video-content h2,.video-content h3{color:#17233b}
    .video-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:25px;padding-top:20px;border-top:1px solid var(--line)}
    .video-tags a{padding:4px 11px;border-radius:99px;background:#eef3fb;color:var(--primary);font-size:12px}
    .video-aside{padding:22px;position:sticky;top:18px}
    .video-aside h2{font-size:18px;margin:0 0 15px}
    .related-video{display:flex;gap:11px;padding:13px 0;border-bottom:1px solid var(--line)}
    .related-video:last-child{border-bottom:0}
    .related-video img{width:92px;height:58px;object-fit:cover;border-radius:7px;background:#e9eef7;flex:0 0 auto}
    .related-video strong{display:block;font-size:13px;line-height:1.5}
    .related-video small{display:block;color:var(--muted);font-size:11px;margin-top:4px}
    .video-more{display:block;margin-top:16px;padding:10px;text-align:center;border-radius:8px;background:#edf3fc;color:var(--primary);font-size:13px;font-weight:700}
    .footer{background:#101d35;color:#cad4e5;padding:48px 0 20px}
    .footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr 1.2fr;gap:35px}
    .footer h3,.footer h4{color:#fff;margin:0 0 14px}
    .footer h3{font-size:20px}
    .footer h4{font-size:15px}
    .footer p{margin:7px 0;font-size:13px;color:#aebbd0}
    .footer-grid>div>a{display:block;margin:7px 0;color:#aebbd0;font-size:13px}
    .footer-grid>div>a:hover{color:#fff}
    .footer-bottom{display:flex;justify-content:space-between;gap:20px;border-top:1px solid rgba(255,255,255,.13);margin-top:35px;padding-top:18px;color:#91a0b8;font-size:12px}
    @media(max-width:1050px){
      .nav-link{padding-left:8px;padding-right:8px}
      .header-inner{gap:12px}
      .logo{min-width:145px}
    }
    @media(max-width:820px){
      .topbar .container{align-items:flex-start;flex-direction:column;gap:0;padding-top:7px;padding-bottom:7px}
      .topbar a{margin-left:0;margin-right:16px}
      .main-nav{display:none}
      .hamburger{display:block}
      .header-btns{margin-left:auto}
      .member-btn{display:none}
      .video-layout{grid-template-columns:1fr}
      .video-aside{position:static}
      .footer-grid{grid-template-columns:repeat(2,1fr)}
    }
    @media(max-width:560px){
      .container{width:min(100% - 28px,1180px)}
      .header-inner{min-height:66px}
      .logo{font-size:16px;min-width:0}
      .logo img{width:29px;height:29px}
      .open-btn{display:none}
      .video-detail-main{padding-top:32px}
      .video-primary{padding:18px}
      .video-heading h1{font-size:26px}
      .video-cover{min-height:210px}
      .video-player iframe,.video-player video{min-height:220px}
      .footer-grid{grid-template-columns:1fr}
      .footer-bottom{display:block}
      .footer-bottom span{display:block;margin-top:7px}
    }