:root{
      --theme:#0B3D91;
      --theme-dark:#082b67;
      --ink:#172033;
      --muted:#687386;
      --line:#e5eaf1;
      --bg:#f5f7fb;
      --card:#fff;
      --shadow:0 16px 42px rgba(20,42,78,.1);
      --radius:18px;
    }
    *{box-sizing:border-box}
    html{scroll-behavior:smooth}
    body{margin:0;color:var(--ink);background:var(--bg);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:#102344;color:#dce7fb;font-size:13px}
    .topbar-inner{min-height:36px;display:flex;align-items:center;justify-content:space-between;gap:20px}
    .topbar-contact{display:flex;gap:22px}
    .topbar a:hover{color:#fff}
    .header{position:relative;z-index:20;background:#fff;border-bottom:1px solid var(--line)}
    .header-inner{height:78px;display:flex;align-items:center;gap:28px}
    .logo{display:inline-flex;align-items:center;gap:10px;font-weight:800;font-size:19px;white-space:nowrap;color:var(--theme)}
    .logo img{width:34px;height:34px;object-fit:contain}
    .main-nav{margin-left:auto}
    .nav-list{display:flex;align-items:stretch;gap:4px;list-style:none;margin:0;padding:0}
    .nav-item{position:relative}
    .nav-link{display:flex;align-items:center;height:78px;padding:0 13px;font-size:15px;white-space:nowrap}
    .nav-link:hover,.nav-item:focus-within>.nav-link{color:var(--theme)}
    .has-arrow:after{content:"";width:6px;height:6px;margin-left:8px;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:300px;padding:20px;background:#fff;border:1px solid var(--line);border-radius:0 0 16px 16px;box-shadow:var(--shadow);opacity:0;visibility:hidden;transition:.2s;pointer-events:none}
    .mega-menu{width:570px}
    .mega-wide{width:850px}
    .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);pointer-events:auto}
    .dropdown-panel:before,.mega-menu:before{content:"";position:absolute;top:-12px;left:0;right:0;height:12px}
    .dropdown-panel>a{display:block;padding:9px 4px;border-bottom:1px solid var(--line);font-size:14px}
    .dropdown-panel>a:hover{color:var(--theme)}
    .dropdown-all,.mega-footer{display:block;margin-top:14px;color:var(--theme);font-weight:700;font-size:14px}
    .mega-title{margin:0 0 14px;color:var(--theme-dark);font-size:16px}
    .mega-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}
    .mega-card{min-width:0;padding:11px;border:1px solid var(--line);border-radius:12px;background:#fbfcfe;transition:.2s}
    .mega-card:hover{border-color:#9bb3dc;transform:translateY(-2px)}
    .mega-card img{width:34px;height:34px;object-fit:contain;margin-bottom:7px}
    .mega-card .video-thumb,.mega-card .product-thumb{width:100%;height:72px;object-fit:cover;border-radius:8px}
    .mega-card strong{display:block;font-size:13px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
    .mega-card p{margin:5px 0 0;color:var(--muted);font-size:11px;line-height:1.5}
    .mega-meta{display:flex;gap:7px;flex-wrap:wrap;color:var(--muted);font-size:11px;margin-top:5px}
    .mega-columns{display:grid;grid-template-columns:170px 1fr;gap:22px}
    .mega-categories{border-right:1px solid var(--line);padding-right:15px}
    .mega-categories>a{display:block;padding:6px 0;color:#536075;font-size:13px}
    .mega-categories>a:hover{color:var(--theme)}
    .header-btns{display:flex;align-items:center;gap:12px;white-space:nowrap}
    .account-btn{padding:9px 16px;background:var(--theme);border-radius:9px;color:#fff;font-size:14px}
    .account-btn:hover{background:var(--theme-dark)}
    .hamburger{display:none;border:0;background:transparent;width:42px;height:42px;padding:8px;cursor:pointer}
    .hamburger span{display:block;height:2px;margin:5px 0;background:var(--ink);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{display:none;position:fixed;inset:0;background:rgba(8,20,42,.5);z-index:40}
    .drawer-overlay.open{display:block}
    .mobile-drawer{position:fixed;top:0;right:-380px;width:min(380px,88vw);height:100vh;overflow:auto;background:#fff;z-index:41;transition:right .25s;padding-bottom:30px}
    .mobile-drawer.open{right:0}
    .drawer-head{display:flex;align-items:center;gap:16px;padding:20px;border-bottom:1px solid var(--line);font-weight:700}
    .drawer-head>:first-child{margin-right:auto}
    .drawer-head a{color:var(--theme)}
    .drawer-close{border:0;background:transparent;font-size:30px;line-height:1;cursor:pointer;color:var(--muted)}
    .drawer-menu{padding:8px 20px}
    .drawer-link,.drawer-toggle{display:block;width:100%;padding:13px 0;border:0;border-bottom:1px solid var(--line);background:none;text-align:left;color:var(--ink);cursor:pointer}
    .drawer-toggle:after{content:"+";float:right;color:var(--theme);font-size:20px}
    .drawer-toggle.active:after{content:"−"}
    .drawer-submenu{display:none;padding:4px 0 8px 14px}
    .drawer-submenu.open{display:block}
    .drawer-submenu a{display:block;padding:8px 0;color:var(--muted);font-size:14px}
    body.drawer-locked{overflow:hidden}
    .video-detail-main{padding:48px 0 76px}
    .video-breadcrumb{display:flex;gap:8px;align-items:center;color:var(--muted);font-size:13px;margin-bottom:22px}
    .video-breadcrumb a:hover{color:var(--theme)}
    .video-layout{display:grid;grid-template-columns:minmax(0,1fr) 330px;gap:28px;align-items:start}
    .video-article,.related-videos{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:0 8px 25px rgba(20,42,78,.05)}
    .video-article{padding:30px}
    .video-kicker{display:inline-flex;padding:5px 11px;border-radius:999px;background:#eaf1ff;color:var(--theme);font-size:13px;font-weight:700}
    .video-article h1{margin:15px 0 12px;font-size:clamp(27px,4vw,42px);line-height:1.25;letter-spacing:-.02em}
    .video-meta{display:flex;flex-wrap:wrap;gap:16px;color:var(--muted);font-size:13px;padding-bottom:22px;border-bottom:1px solid var(--line)}
    .player-wrap{position:relative;overflow:hidden;aspect-ratio:16/9;margin:26px 0;background:#09152b;border-radius:14px}
    .player-wrap video,.player-wrap iframe{width:100%;height:100%;border:0;object-fit:cover}
    .player-fallback{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;color:#dce7fb;background:linear-gradient(135deg,#0b2148,#071021)}
    .player-fallback span{display:grid;place-items:center;width:68px;height:68px;border:1px solid #91b2e8;border-radius:50%;font-size:28px;padding-left:4px}
    .video-summary{padding:16px 18px;border-left:4px solid var(--theme);background:#f3f7ff;color:#4e5d74;border-radius:0 10px 10px 0}
    .video-body{min-width:0;max-width:100%;overflow-x:auto;margin-top:28px;font-size:16px}
    .video-body img,.video-body table{max-width:100%}
    .video-body h2,.video-body h3{color:var(--theme-dark);margin-top:28px}
    .video-body a{color:var(--theme);text-decoration:underline}
    .video-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:28px;padding-top:20px;border-top:1px solid var(--line)}
    .video-tags a{padding:5px 11px;background:#f0f3f8;border-radius:999px;color:#5d6a7d;font-size:12px}
    .video-tags a:hover{background:#e4edff;color:var(--theme)}
    .related-videos{padding:22px;position:sticky;top:20px}
    .related-videos h2{font-size:20px;margin:0 0 15px}
    .related-card{display:grid;grid-template-columns:104px 1fr;gap:12px;padding:13px 0;border-bottom:1px solid var(--line)}
    .related-card:last-child{border-bottom:0}
    .related-card img{width:104px;height:68px;border-radius:8px;object-fit:cover;background:#e9edf4}
    .related-card strong{display:-webkit-box;-webkit-box-orient:vertical;-webkit-line-clamp:2;overflow:hidden;font-size:14px;line-height:1.45}
    .related-card span{display:block;margin-top:5px;color:var(--muted);font-size:12px}
    .more-videos{display:block;margin-top:15px;padding:10px;text-align:center;border:1px solid #b7c9e7;border-radius:9px;color:var(--theme);font-size:14px;font-weight:700}
    .footer{background:#0e1e38;color:#c6d1e2;padding:52px 0 20px}
    .footer .logo{color:#fff}
    .footer-main{display:grid;grid-template-columns:1.6fr 1fr 1fr 1.1fr;gap:38px}
    .footer h3{margin:0 0 15px;color:#fff;font-size:16px}
    .footer p{margin:8px 0;font-size:13px;color:#aebbd0}
    .footer-links{display:grid;gap:8px;font-size:13px}
    .footer-links a:hover,.footer-contact a:hover{color:#fff}
    .footer-bottom{display:flex;justify-content:space-between;gap:20px;border-top:1px solid rgba(255,255,255,.15);margin-top:35px;padding-top:18px;color:#91a2bc;font-size:12px}
    @media(max-width:1050px){
      .main-nav{display:none}
      .hamburger{display:block}
      .video-layout{grid-template-columns:1fr}
      .related-videos{position:static}
      .related-list{display:grid;grid-template-columns:repeat(2,1fr);gap:0 20px}
    }
    @media(max-width:700px){
      .container{width:min(100% - 28px,1180px)}
      .topbar-inner{padding:8px 0;align-items:flex-start;flex-direction:column;gap:2px}
      .topbar-contact{gap:12px;flex-wrap:wrap}
      .header-inner{height:68px;gap:12px}
      .header-btns{margin-left:auto}
      .header-btns>{会员入口}{会员入口抽屉}{会员登录地址}{联系电话}{联系邮箱}
      .account-btn{padding:8px 11px;font-size:12px}
      .video-detail-main{padding:28px 0 52px}
      .video-article{padding:19px}
      .video-article h1{font-size:28px}
      .video-meta{gap:8px 13px}
      .related-list{display:block}
      .footer-main{grid-template-columns:1fr 1fr;gap:28px 18px}
      .footer-brand{grid-column:1/-1}
      .footer-bottom{display:block}
      .footer-bottom span{display:block;margin-top:7px}
    }
    @media(max-width:430px){
      .account-btn{display:none}
      .footer-main{grid-template-columns:1fr}
    }