:root{--theme:#0B3D91;--ink:#10233f;--muted:#66758a;--ice:#eef6fc;--line:#d9e4ef;--white:#fff;--deep:#071a33}
    *{box-sizing:border-box}
    html{scroll-behavior:smooth}
    body{margin:0;color:var(--ink);background:#f6f9fc;font-family:"Microsoft YaHei","PingFang SC",Arial,sans-serif;line-height:1.6}
    a{color:inherit;text-decoration:none}
    img{max-width:100%;display:block}
    button{font:inherit}
    .container{width:min(1180px,calc(100% - 40px));margin:auto}
    .topbar{background:var(--deep);color:#dbe9f7;font-size:13px}
    .topbar-inner{min-height:34px;display:flex;align-items:center;justify-content:space-between;gap:20px}
    .topbar-contact{display:flex;gap:22px}
    .topbar a{color:#dbe9f7}
    .header{position:relative;z-index:20;background:var(--white);border-bottom:1px solid var(--line)}
    .header-inner{height:76px;display:flex;align-items:center;gap:34px}
    .logo{display:flex;align-items:center;gap:10px;min-width:190px;color:var(--theme);font-size:19px;font-weight:800}
    .logo img{width:34px;height:34px;object-fit:contain}
    .main-nav{flex:1}
    .nav-list{display:flex;align-items:stretch;justify-content:center;gap:4px;padding:0;margin:0;list-style:none}
    .nav-item{position:relative}
    .nav-link{display:flex;align-items:center;gap:6px;height:76px;padding:0 14px;color:#263a52;font-size:15px;white-space:nowrap}
    .nav-link:hover,.nav-link:focus{color:var(--theme)}
    .has-arrow:after{content:"";width:6px;height:6px;border-right:1px solid currentColor;border-bottom:1px solid currentColor;transform:rotate(45deg);margin-top:-4px}
    .dropdown-panel,.mega-menu{position:absolute;top:calc(100% + 1px);left:50%;width:320px;padding:22px;background:#fff;border:1px solid var(--line);box-shadow:0 18px 40px rgba(10,38,69,.14);opacity:0;visibility:hidden;transform:translate(-50%,8px);transition:.2s ease}
    .mega-menu{width:720px}
    .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:translate(-50%,0)}
    .dropdown-panel:before,.mega-menu:before{content:"";position:absolute;left:0;right:0;top:-12px;height:12px}
    .panel-title{margin:0 0 13px;color:var(--theme);font-size:15px}
    .panel-list{display:grid;gap:8px}
    .panel-list a{display:block;color:#42556b;font-size:13px}
    .panel-list a:hover{color:var(--theme)}
    .mega-grid{display:grid;grid-template-columns:1fr 1fr;gap:26px}
    .mega-column+.mega-column{border-left:1px solid var(--line);padding-left:26px}
    .mega-card{display:flex;gap:10px;padding:9px 0;border-bottom:1px solid #edf2f7}
    .mega-card:last-child{border-bottom:0}
    .mega-card img{width:38px;height:38px;object-fit:cover;border-radius:6px;background:var(--ice);flex:0 0 auto}
    .mega-card span{min-width:0}
    .mega-card strong,.mega-card small{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
    .mega-card strong{font-size:13px;color:#253d57}
    .mega-card small{font-size:11px;color:var(--muted);margin-top:2px}
    .mega-footer{display:block;margin:18px -22px -22px;padding:12px 22px;background:var(--ice);color:var(--theme);font-size:13px;font-weight:700}
    .header-btns{display:flex;align-items:center;gap:10px;white-space:nowrap}
    .member-btn,.open-account{padding:8px 13px;border:1px solid var(--theme);font-size:13px}
    .member-btn{color:var(--theme)}
    .open-account{background:var(--theme);color:#fff}
    .hamburger{display:none;width:40px;height:38px;padding:8px;border:1px solid var(--line);background:#fff;cursor:pointer}
    .hamburger span{display:block;width:21px;height:2px;margin:4px auto;background:var(--theme);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(4,19,37,.45);opacity:0;visibility:hidden;z-index:30;transition:.2s}
    .drawer-overlay.open{opacity:1;visibility:visible}
    .mobile-drawer{position:fixed;top:0;right:0;width:min(380px,88vw);height:100vh;overflow:auto;background:#fff;z-index:31;transform:translateX(100%);transition:.25s ease;box-shadow:-12px 0 30px rgba(4,19,37,.18)}
    .mobile-drawer.open{transform:translateX(0)}
    .drawer-head{display:flex;align-items:center;gap:14px;padding:20px;border-bottom:1px solid var(--line);color:var(--theme);font-weight:700}
    .drawer-head span{flex:1}
    .drawer-head a{padding:6px 10px;background:var(--theme);color:#fff;font-size:13px}
    .drawer-close{border:0;background:transparent;color:var(--theme);font-size:25px;line-height:1;cursor:pointer}
    .drawer-menu{padding:10px 20px 30px}
    .drawer-link,.drawer-toggle{display:block;width:100%;padding:14px 0;border:0;border-bottom:1px solid var(--line);background:none;color:var(--ink);text-align:left;cursor:pointer;font-size:15px}
    .drawer-toggle:after{content:"+";float:right;color:var(--theme);font-size:20px;line-height:1}
    .drawer-toggle.active:after{content:"−"}
    .drawer-submenu{display:none;padding:5px 0 8px 16px;background:#f7fafc}
    .drawer-submenu.open{display:block}
    .drawer-submenu a{display:block;padding:8px 0;color:var(--muted);font-size:13px}
    .footer{margin-top:70px;background:var(--deep);color:#c9d7e7}
    .footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;gap:38px;padding:48px 0 36px}
    .footer strong{color:#fff;font-size:19px}
    .footer h3{margin:0 0 14px;color:#fff;font-size:15px}
    .footer p{margin:8px 0;font-size:13px}
    .footer-grid>div:not(.footer-brand) a{display:block;margin:8px 0;color:#c9d7e7;font-size:13px}
    .footer-grid a:hover{color:#fff}
    .footer-bottom{padding:18px 0;border-top:1px solid rgba(255,255,255,.14);font-size:12px;color:#9eb1c7}
    .video-detail-main{padding:52px 0 10px}
    .video-detail-main .video-breadcrumb{margin-bottom:18px;color:var(--muted);font-size:13px}
    .video-detail-main .video-breadcrumb a{color:var(--theme)}
    .video-detail-main .video-header{max-width:880px;margin:0 auto 25px;text-align:center}
    .video-detail-main .video-header h1{margin:0 0 13px;color:var(--deep);font-size:clamp(28px,4vw,46px);line-height:1.25}
    .video-detail-main .video-meta{display:flex;justify-content:center;flex-wrap:wrap;gap:18px;color:var(--muted);font-size:13px}
    .video-detail-main .video-stage{max-width:1000px;margin:0 auto;background:#061526;border:10px solid #0d2948;box-shadow:0 18px 45px rgba(9,35,63,.18)}
    .video-detail-main .video-player{width:100%;min-height:520px;display:grid;place-items:center;background:linear-gradient(145deg,#092748,#071629);color:#d7eafa}
    .video-detail-main .video-cover{width:100%;max-height:560px;object-fit:cover;opacity:.82}
    .video-detail-main .player-fallback{position:absolute;display:grid;place-items:center;gap:10px;text-align:center}
    .video-detail-main .play-mark{width:68px;height:68px;display:grid;place-items:center;border:1px solid #a9d8ff;border-radius:50%;color:#fff;font-size:28px}
    .video-detail-main .player-caption{margin:0;color:#b9d1e8;font-size:13px}
    .video-detail-main .video-content-wrap{display:grid;grid-template-columns:minmax(0,1fr) 300px;gap:30px;max-width:1000px;margin:35px auto 0}
    .video-detail-main .video-article,.video-detail-main .related-videos{background:#fff;border:1px solid var(--line)}
    .video-detail-main .video-article{padding:30px}
    .video-detail-main .section-title{margin:0 0 16px;color:var(--deep);font-size:20px}
    .video-detail-main .video-intro{padding:16px 18px;background:var(--ice);border-left:3px solid var(--theme);color:#40566e}
    .video-detail-main .video-body{min-width:0;max-width:100%;overflow-x:auto;color:#405166;font-size:15px}
    .video-detail-main .video-body img,.video-detail-main .video-body table{max-width:100%}
    .video-detail-main .video-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:24px;padding-top:20px;border-top:1px solid var(--line);font-size:13px}
    .video-detail-main .video-tags a{padding:5px 10px;background:#eef4f9;color:var(--theme)}
    .video-detail-main .related-videos{padding:22px}
    .video-detail-main .related-list{display:grid;gap:16px}
    .video-detail-main .related-card{display:grid;grid-template-columns:96px 1fr;gap:10px;padding-bottom:15px;border-bottom:1px solid var(--line)}
    .video-detail-main .related-card:last-child{border-bottom:0;padding-bottom:0}
    .video-detail-main .related-card img{width:96px;height:62px;object-fit:cover;background:var(--ice)}
    .video-detail-main .related-card strong{display:block;color:var(--ink);font-size:13px;line-height:1.45}
    .video-detail-main .related-card small{display:block;margin-top:5px;color:var(--muted);font-size:11px}
    .video-detail-main .video-more{display:inline-block;margin-top:20px;color:var(--theme);font-size:13px;font-weight:700}
    @media(max-width:980px){
      .main-nav{display:none}
      .header-inner{height:68px;justify-content:space-between}
      .header-btns{margin-left:auto}
      .hamburger{display:block}
      .member-btn{display:none}
      .nav-link{height:68px}
      .video-detail-main .video-content-wrap{grid-template-columns:1fr}
      .related-videos{order:2}
    }
    @media(max-width:640px){
      .container{width:min(100% - 28px,1180px)}
      .topbar-inner{align-items:flex-start;flex-direction:column;gap:2px;padding:8px 0}
      .topbar-contact{gap:12px;flex-wrap:wrap}
      .logo{min-width:0;font-size:16px}
      .open-account{padding:7px 9px;font-size:12px}
      .video-detail-main{padding-top:30px}
      .video-detail-main .video-player{min-height:260px}
      .video-detail-main .video-stage{border-width:5px}
      .video-detail-main .video-article{padding:20px}
      .footer-grid{grid-template-columns:1fr 1fr;gap:25px}
      .footer-brand{grid-column:1/-1}
    }