:root{color-scheme:dark;--bg:#080A0D;--surface:#0D1015;--card:#12161C;--secondary:#171C23;--hover:#1B2129;--ink:#F5F7FA;--body:#C7CDD5;--muted:#9098A3;--blue:#6EA8FF;--edge:rgba(255,255,255,.09)}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);font:16px/1.8 Arial,"PingFang SC","Microsoft YaHei",sans-serif;color:var(--body)}img{display:block;max-width:100%;height:auto}a{color:inherit;text-decoration:none}a:hover{color:var(--blue)}button{font:inherit;cursor:pointer}p{margin:0 0 16px}h1,h2,h3{color:var(--ink);line-height:1.35;letter-spacing:-.025em;margin:0 0 18px}h1{font-size:40px}h2{font-size:26px}h3{font-size:20px}a:focus-visible,button:focus-visible,summary:focus-visible{outline:2px solid var(--blue);outline-offset:4px}.container{width:min(1200px,calc(100% - 48px));margin-inline:auto}.prose{max-width:820px}.section{margin-block:54px}.section-head{margin-bottom:24px}.section-head h2{margin:7px 0 0}.eyebrow,.chapter-tag{font-size:12px;letter-spacing:.15em;font-weight:700;color:#8ED8FF;text-transform:uppercase}.muted{color:var(--muted)}.blue{color:var(--blue)}.lead{font-size:17px;color:#d7dee8;line-height:1.85}.skip-link{position:absolute;top:-90px;left:12px;z-index:10000;background:white;color:black;padding:7px 14px}.skip-link:focus{top:10px}
.site-header{height:74px;background:rgba(8,10,13,.96);border-bottom:1px solid var(--edge);position:relative;z-index:20}.header-inner{width:min(1200px,calc(100% - 48px));margin:auto;position:relative;display:flex;justify-content:space-between;align-items:center;height:100%}.menu-trigger{width:44px;height:44px;display:flex;flex-direction:column;gap:5px;align-items:center;justify-content:center;background:transparent;border:1px solid var(--edge);border-radius:11px;color:white}.menu-trigger span{width:20px;height:2px;background:#dce2eb;border-radius:3px}.brand-logo{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);display:flex;justify-content:center;align-items:center;max-width:34%}.brand-logo img{height:35px;width:auto;max-width:100%;object-fit:contain}.brand-fallback{font-size:21px;color:#e9eff8;font-weight:800;white-space:nowrap;letter-spacing:.04em}.enter-link{border:1px solid #5c7cfa;background:#172749;color:#e8f0ff;padding:8px 18px;border-radius:999px;font-size:14px;font-weight:700;line-height:24px;white-space:nowrap}.enter-link:hover{background:#263d6c;color:white}.channel-bar{background:#0D1015;border-bottom:1px solid var(--edge)}.channel-inner{max-width:1200px;margin:auto;display:flex;align-items:stretch;justify-content:space-between;gap:8px;height:48px;overflow-x:auto;overscroll-behavior-x:contain;scrollbar-width:thin;scrollbar-color:#35465d transparent}.channel-inner a{display:flex;align-items:center;justify-content:center;white-space:nowrap;padding:0 13px;font-size:14px;color:#c7cdd5;border-bottom:2px solid transparent}.channel-inner a:hover,.channel-inner a.active{color:var(--blue);border-color:var(--blue)}
.drawer-overlay,.site-drawer{position:fixed;visibility:hidden;pointer-events:none;transition:transform .22s ease,opacity .22s ease,visibility .22s;z-index:80}.drawer-overlay{inset:0;background:rgba(0,0,0,.68);opacity:0;z-index:79}.drawer-overlay.is-open{visibility:visible;pointer-events:auto;opacity:1}.site-drawer{inset:0 auto 0 0;width:420px;max-width:100%;background:#0D1015;transform:translateX(-101%);display:flex;flex-direction:column;box-shadow:15px 0 70px #0008}.site-drawer.is-open{transform:translateX(0);visibility:visible;pointer-events:auto}.drawer-header{min-height:106px;display:flex;align-items:center;justify-content:space-between;gap:12px;padding:20px 24px;border-bottom:1px solid var(--edge)}.drawer-brand img{max-height:34px;width:auto;object-fit:contain}.drawer-brand strong{font-size:22px;color:white}.drawer-brand small{display:block;color:var(--muted);font-size:12px}.close-trigger{width:40px;height:40px;background:#171c23;border:1px solid var(--edge);border-radius:10px;color:white;font-size:28px;line-height:1}.drawer-body{padding:12px 24px 30px;overflow-y:auto;overscroll-behavior:contain}.drawer-group{padding:15px 0;border-bottom:1px solid var(--edge)}.drawer-group h2{font-size:13px;color:#8ed8ff;letter-spacing:.08em;margin:0 0 10px}.drawer-items{display:grid;grid-template-columns:1fr 1fr;gap:5px}.drawer-items a{padding:6px 10px;border-left:2px solid transparent;border-radius:4px;font-size:14px}.drawer-items a.selected{color:var(--blue);border-left-color:var(--blue);background:#151e2d}
.hero{padding:48px 0 22px;display:grid;grid-template-columns:minmax(0,56fr) minmax(0,44fr);align-items:center;gap:36px}.hero h1{max-width:650px;margin-top:10px}.hero-copy p{max-width:650px}.text-actions{display:flex;flex-wrap:wrap;gap:18px;margin-top:24px}.text-actions a,.inline-link{color:#8ed8ff;font-weight:700;border-bottom:1px solid #5175a0}.text-actions a:hover,.inline-link:hover{color:white}.hero-media{min-width:0}.media{width:100%;max-width:100%;min-width:0;border-radius:14px;background:var(--surface);overflow:hidden;display:flex;align-items:center;justify-content:center;border:1px solid var(--edge)}.media img{width:100%;height:100%;max-width:100%;max-height:100%;object-fit:contain;object-position:center center}.media-square{height:175px}.media-wide{height:180px}.media-banner{height:250px}.media-device{height:350px}.media-gif{height:160px}.media-hero{height:305px}.media-placeholder{background:radial-gradient(circle at 65% 30%,rgba(92,124,250,.10),transparent 42%),linear-gradient(145deg,#131b25,#0d1015)}.placeholder-mark{display:block;height:40%;aspect-ratio:1;border:1px solid rgba(142,216,255,.15);transform:rotate(45deg);border-radius:17px;background:linear-gradient(135deg,transparent,rgba(142,216,255,.05))}
.quick-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.quick-item,.small-card,.knowledge-card{padding:22px;border:1px solid var(--edge);background:var(--card);border-radius:13px;min-width:0}.quick-item .num{font-size:12px;color:var(--blue);font-weight:700}.quick-item h3{margin:10px 0}.quick-item p,.small-card p{font-size:14px;color:#aeb6c2}.quick-item a,.small-card a{font-size:14px;color:#8ed8ff}.split{display:grid;grid-template-columns:minmax(0,1.4fr) minmax(0,1fr);gap:28px;align-items:start}.split.equal{grid-template-columns:repeat(2,minmax(0,1fr))}.split.feature-split{grid-template-columns:minmax(0,1.65fr) minmax(0,1fr)}.split.image-split{align-items:center}.dark-panel{background:var(--surface);border:1px solid var(--edge);border-radius:14px;padding:24px}.dark-panel h3{margin-top:0}.link-stack{display:grid;gap:12px}.link-stack a,.related-link{padding:12px 16px;border:1px solid var(--edge);border-radius:9px;background:var(--card);display:flex;justify-content:space-between;gap:10px}.link-stack a:hover,.related-link:hover{background:var(--hover);border-color:#3d5674}.card-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:18px}.visual-card{min-width:0;background:var(--card);border:1px solid var(--edge);border-radius:14px;overflow:hidden}.visual-card .media{border:0;border-radius:0}.visual-card .card-body{padding:17px}.visual-card h3{font-size:18px;margin:0 0 9px}.visual-card p{font-size:14px;margin-bottom:10px;color:#b2bac5}.visual-card a{font-size:14px;color:#8ed8ff}.visual-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.number-list{display:grid;gap:0;counter-reset:items}.number-item{display:grid;grid-template-columns:48px minmax(0,1fr);gap:16px;border-top:1px solid var(--edge);padding:20px 0}.number-item .number{font-size:24px;color:#779bce;line-height:1.3;font-weight:700}.number-item h3{margin:0 0 7px}.number-item p{margin:0 0 8px;color:#b4bdca}.number-item a{font-size:14px;color:#8ed8ff}.mini-list{display:grid;gap:14px}.mini-list article{border-bottom:1px solid var(--edge);padding-bottom:12px}.mini-list h3{margin-bottom:5px}.mini-list p{font-size:14px}.notice-strip{border:1px solid #2b3e56;background:linear-gradient(100deg,#101721,#101218);padding:23px 27px;border-radius:12px}.notice-strip h2{font-size:21px}.article-header{padding:48px 0 26px;border-bottom:1px solid var(--edge)}.article-header h1{font-size:34px;max-width:1000px}.article-header p{max-width:820px;color:#b8c2cf}.breadcrumb{font-size:13px;color:var(--muted);margin-bottom:18px}.breadcrumb span{margin:0 6px}.article-shell{padding-block:40px;display:grid;grid-template-columns:minmax(0,820px) minmax(230px,1fr);gap:48px;align-items:start}.article-shell.single{display:block}.article-shell.single .article-main{max-width:820px}.article-section{margin:0 0 42px}.article-section h2{margin:10px 0 17px}.article-section p{font-size:16px;line-height:1.85;color:#c5cbd4}.article-aside{position:sticky;top:18px}.aside-heading{font-size:17px}.article-aside a{display:block;padding:12px 0;border-bottom:1px solid var(--edge);font-size:14px}.article-main .media{margin:20px 0 28px}.related{margin-bottom:65px}.related-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.definition-grid,.topic-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.topic-list .small-card{min-width:0}.faq-list{max-width:820px}.faq-list details{border-bottom:1px solid var(--edge);padding:18px 0}.faq-list summary{cursor:pointer;color:var(--ink);font-size:17px;font-weight:700}.faq-list p{margin:12px 0 0}.site-footer{background:#050608;border-top:1px solid var(--edge);padding:50px 0 20px}.footer-grid{display:grid;grid-template-columns:2fr repeat(3,1fr);gap:35px}.site-footer h2{font-size:16px;margin-bottom:18px}.site-footer a:not(.footer-brand a){display:block;color:#abb5c2;font-size:14px;margin-bottom:9px}.footer-brand img{max-height:36px;object-fit:contain;width:auto}.footer-brand strong{font-size:23px;color:white}.footer-brand p{font-size:14px;color:#929ba9;margin-top:17px}.footer-bottom{display:flex;justify-content:space-between;gap:30px;border-top:1px solid var(--edge);padding-top:20px;margin-top:38px;color:#929ba9;font-size:13px}.footer-bottom p{margin:0;max-width:700px}.back-to-top{position:fixed;bottom:25px;right:22px;z-index:19;border:1px solid #385375;background:#161f2b;color:#eef5ff;width:42px;height:42px;border-radius:12px;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .15s}.back-to-top.visible{opacity:1;visibility:visible;pointer-events:auto}
@media(max-width:1100px){.container,.header-inner{width:calc(100% - 40px)}.channel-inner{justify-content:flex-start}.card-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.article-shell{grid-template-columns:minmax(0,1fr) 235px;gap:26px}.footer-grid{grid-template-columns:1.5fr 1fr 1fr;gap:25px}.footer-grid>div:last-child{grid-column:2/4}.media-hero{height:260px}}
@media(max-width:800px){.hero{gap:24px}.hero h1{font-size:32px}.quick-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.split,.split.equal,.split.feature-split{grid-template-columns:1fr}.article-shell{display:block}.article-aside{position:static;margin-top:36px}.visual-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.related-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:600px){body{font-size:15px}.container,.header-inner{width:calc(100% - 32px)}h1{font-size:29px}h2{font-size:22px}h3{font-size:18px}.section{margin-block:34px}.section-head{margin-bottom:17px}.site-header{height:62px}.menu-trigger{width:40px;height:40px}.brand-logo img{height:27px;max-width:100%}.brand-fallback{font-size:16px}.enter-link{font-size:12px;height:38px;padding:7px 11px;line-height:22px}.channel-inner{height:44px}.channel-inner a{padding:0 14px;font-size:13px}.site-drawer{width:min(86vw,340px)}.drawer-header{padding:15px}.drawer-body{padding:10px 15px 30px}.hero{display:flex;flex-direction:column-reverse;align-items:stretch;padding:22px 0 10px;gap:19px}.hero h1{font-size:29px}.lead{font-size:15px}.hero .media-hero{height:195px}.text-actions{gap:16px;margin-top:15px}.media-hero{height:190px}.media-wide,.media-square{height:145px}.media-banner{height:140px}.media-device{height:310px}.media-gif{height:135px}.card-grid,.visual-grid{gap:12px}.visual-card .card-body{padding:12px}.visual-card h3{font-size:16px}.visual-card p{font-size:13px}.quick-item,.small-card,.knowledge-card{padding:16px}.quick-item p,.small-card p{font-size:13px}.dark-panel{padding:18px}.number-item{grid-template-columns:32px minmax(0,1fr);gap:12px}.number-item .number{font-size:18px}.article-header{padding:28px 0 20px}.article-header h1{font-size:26px}.article-shell{padding-top:25px}.article-section{margin-bottom:32px}.article-section p{font-size:15px}.related-grid{grid-template-columns:1fr}.footer-grid{grid-template-columns:1fr 1fr;gap:24px}.footer-grid>div:first-child{grid-column:1/-1}.footer-grid>div:last-child{grid-column:auto}.footer-bottom{display:block}.footer-bottom p{margin-top:8px}.site-footer{padding-top:34px}.definition-grid,.topic-list{grid-template-columns:1fr}}
@media(max-width:359px){.brand-logo{max-width:29%}.brand-fallback{font-size:14px}.brand-logo img{height:24px}.enter-link{padding:6px 8px;font-size:11px}.quick-grid{grid-template-columns:1fr}.card-grid{grid-template-columns:1fr 1fr}.visual-card .media{height:115px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition-duration:.01ms!important;animation-duration:.01ms!important}}