:root{--theme:#0B3D91;--ink:#152238;--muted:#6d7890;--line:#e5eaf1;--bg:#f5f7fb;--white:#fff}
    *{box-sizing:border-box}
    html,body{margin:0;padding:0;color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"Microsoft YaHei","PingFang SC",Arial,sans-serif;background:var(--bg);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% - 32px));margin:auto}
    .topbar{background:#101b30;color:#d8e0ef;font-size:13px}
    .topbar .container{height:38px;display:flex;align-items:center;justify-content:space-between}
    .topbar-links{display:flex;gap:22px}.topbar a:hover{color:#fff}
    .header{background:#fff;border-bottom:1px solid var(--line);position:relative;z-index:20}
    .header-inner{height:78px;display:flex;align-items:center;gap:34px}
    .logo{display:flex;align-items:center;gap:10px;white-space:nowrap;font-size:20px;font-weight:800;color:var(--theme)}
    .logo img{width:38px;height:38px;object-fit:contain}
    .main-nav{flex:1}.nav-list{display:flex;align-items:center;gap:4px;list-style:none;margin:0;padding:0}
    .nav-item{position:relative}.nav-link{display:block;padding:27px 15px;font-size:15px;font-weight:600}
    .nav-link:hover{color:var(--theme);background:#f7f9fd}
    .has-arrow:after{content:"⌄";font-size:12px;margin-left:6px;color:#8490a5}
    .dropdown-panel,.mega-menu{position:absolute;top:calc(100% - 1px);left:50%;transform:translateX(-50%);background:#fff;border:1px solid var(--line);border-radius:0 0 12px 12px;box-shadow:0 18px 45px #1826421c;opacity:0;visibility:hidden;pointer-events:none;transition:.2s;min-width:285px;padding:20px}
    .mega-menu{width:650px}.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;pointer-events:auto}
    .dropdown-panel:before,.mega-menu:before{content:"";position:absolute;left:0;right:0;top:-12px;height:12px}
    .drop-title,.mega-title{margin:0 0 13px;font-size:14px;font-weight:800;color:var(--theme)}
    .drop-list,.mega-links{display:grid;gap:8px}.drop-list a,.mega-links a{font-size:13px;color:#46536b;padding:3px 0}.drop-list a:hover,.mega-links a:hover{color:var(--theme)}
    .mega-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}
    .mega-card{display:flex;gap:9px;padding:10px;border:1px solid var(--line);border-radius:9px;background:#fbfcff}
    .mega-card:hover{border-color:#9eb4d8}.mega-card img{width:30px;height:30px;object-fit:contain}.mega-card span{min-width:0}
    .mega-card strong,.mega-card small{display:block}.mega-card strong{font-size:13px}.mega-card small{font-size:11px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
    .mega-columns{display:grid;grid-template-columns:1fr 1fr;gap:28px}.mega-footer{display:block;margin-top:16px;padding-top:12px;border-top:1px solid var(--line);font-size:13px;color:var(--theme);font-weight:700}
    .header-btns{display:flex;align-items:center;gap:14px;white-space:nowrap}.member-btn{background:var(--theme);color:#fff;padding:9px 14px;border-radius:7px;font-size:13px}.account-link{font-size:14px;color:var(--theme);font-weight:700}
    .hamburger{display:none;border:0;background:transparent;padding:8px;cursor:pointer}.hamburger span{display:block;width:23px;height:2px;background:var(--ink);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{display:none;position:fixed;inset:0;background:#08152b80;z-index:40}.drawer-overlay.open{display:block}
    .mobile-drawer{position:fixed;z-index:50;right:0;top:0;bottom:0;width:min(360px,88vw);background:#fff;transform:translateX(100%);transition:.25s;overflow:auto}.mobile-drawer.open{transform:translateX(0)}
    .drawer-head{height:70px;display:flex;align-items:center;gap:15px;padding:0 20px;border-bottom:1px solid var(--line);color:var(--theme)}.drawer-head strong{flex:1}.drawer-head a{font-size:13px}.drawer-close{border:0;background:none;font-size:28px;color:#657187;cursor:pointer}
    .drawer-menu{padding:12px 20px}.drawer-link,.drawer-toggle{display:block;width:100%;padding:13px 0;border:0;border-bottom:1px solid #edf0f5;background:none;text-align:left;font-weight:600;color:var(--ink);cursor:pointer}.drawer-group .drawer-toggle:after{content:"＋";float:right;color:#8995aa}.drawer-toggle.active:after{content:"－"}.drawer-submenu{display:none;padding:5px 0 8px 14px}.drawer-submenu.open{display:block}.drawer-submenu a{display:block;padding:7px 0;font-size:13px;color:var(--muted)}
    .footer{margin-top:70px;background:#101b30;color:#b8c3d6;padding:52px 0 18px}.footer-grid{display:grid;grid-template-columns:1.6fr 1fr 1fr 1.2fr;gap:35px}.footer h3{color:#fff;font-size:15px;margin:0 0 15px}.footer a{display:block;font-size:13px;margin:8px 0}.footer a:hover{color:#fff}.footer-brand strong{display:block;color:#fff;font-size:21px;margin-bottom:12px}.footer p{font-size:13px;margin:7px 0}.footer-bottom{display:flex;justify-content:space-between;border-top:1px solid #334158;margin-top:34px;padding-top:17px;font-size:12px;color:#8996ab}
    .video-detail-main{padding:46px 0 10px}.video-detail-main .crumb{font-size:13px;color:var(--muted);margin-bottom:18px}.video-detail-main .crumb a{color:var(--theme)}
    .video-detail-layout{display:grid;grid-template-columns:minmax(0,1fr) 310px;gap:28px;align-items:start}
    .video-primary,.video-side{background:#fff;border:1px solid var(--line);border-radius:14px;box-shadow:0 8px 25px #1728490a}
    .video-primary{overflow:hidden}.video-heading{padding:25px 28px 17px}.video-heading h1{font-size:30px;line-height:1.3;margin:0 0 13px;color:#14223a}.video-meta{display:flex;flex-wrap:wrap;gap:15px;color:var(--muted);font-size:13px}
    .video-player{background:#0c1424;min-height:430px;display:flex;align-items:center;justify-content:center;color:#fff;position:relative}.video-player video,.video-player iframe{width:100%;min-height:430px;border:0}.video-player .player-placeholder{width:100%;min-height:430px;display:flex;align-items:center;justify-content:center;background:linear-gradient(135deg,#101c35,#172d57);font-size:16px}
    .video-player .play-mark{display:flex;align-items:center;justify-content:center;width:76px;height:76px;border-radius:50%;background:#fff;color:var(--theme);font-size:28px;padding-left:5px;box-shadow:0 8px 25px #0005}
    .video-body{padding:28px;min-width:0;max-width:100%;overflow-x:auto}.video-intro{padding:15px 18px;background:#f4f7fc;border-left:4px solid var(--theme);color:#53627a;margin-bottom:25px}.video-content{overflow-wrap:anywhere}.video-content img,.video-content table{max-width:100%}.video-tags{display:flex;gap:8px;flex-wrap:wrap;margin-top:24px;padding-top:20px;border-top:1px solid var(--line)}.video-tags a{padding:4px 10px;border-radius:20px;background:#eef3fb;color:var(--theme);font-size:12px}
    .video-side{padding:22px;position:sticky;top:20px}.video-side h2{font-size:18px;margin:0 0 16px}.related-video{display:flex;gap:10px;padding:12px 0;border-top:1px solid var(--line)}.related-video:first-of-type{border-top:0}.related-video img{width:92px;height:60px;object-fit:cover;border-radius:6px;background:#e9edf4}.related-video strong{font-size:13px;line-height:1.5;display:block}.related-video small{font-size:11px;color:var(--muted)}
    .video-actions{display:flex;justify-content:space-between;gap:10px;margin-top:28px;padding-top:20px;border-top:1px solid var(--line)}.video-actions a{color:var(--theme);font-weight:700;font-size:13px}
    @media(max-width:900px){.main-nav{display:none}.hamburger{display:block}.header-inner{height:68px}.account-link{display:none}.footer-grid{grid-template-columns:repeat(2,1fr)}.video-detail-layout{grid-template-columns:1fr}.video-side{position:static}.video-player,.video-player video,.video-player iframe,.video-player .player-placeholder{min-height:320px}}
    @media(max-width:600px){.topbar .container{height:auto;min-height:38px;gap:8px;padding-top:8px;padding-bottom:8px;align-items:flex-start}.topbar-links{gap:8px;flex-direction:column;text-align:right}.logo{font-size:17px}.member-btn{display:none}.video-detail-main{padding-top:28px}.video-heading{padding:20px}.video-heading h1{font-size:23px}.video-body{padding:20px}.video-player,.video-player video,.video-player iframe,.video-player .player-placeholder{min-height:230px}.footer-grid{grid-template-columns:1fr;gap:24px}.footer-bottom{display:block}.footer-bottom span{display:block;margin:5px 0}.mega-menu{display:none}}