:root{--paper:#f6fafc;--white:#fff;--mist:#eaf6fa;--mist2:#edf4f8;--cyan:#25c8d1;--sky:#25b6e8;--blue:#1787db;--navy:#174b78;--ink:#183a56;--body:#31485d;--muted:#687d8e;--line:#dce9f0;--footer:#123653;--radius:16px;--width:1180px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:32px}body{margin:0;font-family:Arial,'PingFang SC','Microsoft YaHei',sans-serif;background:var(--paper);color:var(--body);font-size:16px;line-height:1.8;overflow-x:hidden}a{color:var(--navy);text-underline-offset:4px}a:hover{color:var(--blue)}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--cyan);outline-offset:3px}button{font:inherit;cursor:pointer}img{max-width:100%}.wrap{width:min(calc(100% - 56px),var(--width));margin:auto}.skip-link{position:absolute;top:-100px;left:15px;z-index:1000;background:white;padding:10px 16px}.skip-link:focus{top:10px}.site-header{background:#fff;position:relative;z-index:15;border-bottom:1px solid var(--line)}.topbar{height:72px;display:flex;align-items:center;gap:24px}.brand{display:inline-flex;align-items:center;min-width:0;text-decoration:none;flex-shrink:0}.brand img{display:block;width:auto;height:auto;max-height:38px;max-width:245px;object-fit:contain}.brand-fallback{font-size:23px;font-weight:800;color:var(--navy);line-height:1.15}.brand-fallback small{display:block;letter-spacing:2px;font-size:10px;color:#1787db}.brand-note{margin:auto;color:var(--muted);font-size:14px;letter-spacing:2px}.entry-button{display:inline-flex;align-items:center;justify-content:center;gap:12px;background:var(--navy);color:#fff;text-decoration:none;border-radius:9px;padding:10px 20px;min-height:42px;white-space:nowrap;font-size:14px;font-weight:700}.entry-button:hover{background:#106a9c;color:#fff}.channel-nav{background:var(--navy)}.channel-inner{display:flex;align-items:center;justify-content:space-between;gap:10px;min-height:48px}.channel-inner a{display:inline-flex;align-items:center;min-height:48px;color:#e9f7ff;text-decoration:none;padding:0 10px;border-bottom:3px solid transparent;white-space:nowrap;font-size:14px}.channel-inner a:hover,.channel-inner a[aria-current=page]{color:#fff;border-bottom-color:var(--cyan)}.menu-toggle{display:none;width:40px;height:40px;border:1px solid var(--line);background:#fff;border-radius:9px;flex-direction:column;align-items:center;justify-content:center;gap:5px}.menu-toggle span{width:19px;height:2px;background:var(--navy);border-radius:2px}.drawer-backdrop,.mobile-drawer,.mobile-bottom{display:none}.back-top{position:fixed;bottom:26px;right:24px;z-index:20;border:none;background:var(--navy);color:#fff;border-radius:50%;width:43px;height:43px}.back-top[hidden]{display:none}h1,h2,h3{color:var(--ink);line-height:1.38;margin:0 0 18px}h1{font-size:clamp(32px,3vw,36px);letter-spacing:-.5px}h2{font-size:26px}h3{font-size:20px}p{margin:0 0 17px}section{margin-top:56px}main{min-height:60vh}.eyebrow{color:#1375a1;font-size:13px;font-weight:800;letter-spacing:2px;text-transform:uppercase;display:block;margin-bottom:13px}.lead{font-size:17px;line-height:1.85;color:#446074}.page-heading{padding-top:48px;max-width:870px}.page-heading p{max-width:800px}.hero{display:grid;grid-template-columns:minmax(0,1.12fr) minmax(0,.88fr);gap:50px;align-items:center;padding-top:42px}.hero h1{font-size:clamp(38px,3.4vw,42px)}.hero .lead{font-size:17px}.hero-links,.inline-links{display:flex;gap:13px;flex-wrap:wrap;margin-top:24px}.primary-link,.secondary-link{display:inline-block;padding:11px 20px;border-radius:9px;font-weight:700;text-decoration:none}.primary-link{background:var(--navy);color:#fff}.primary-link:hover{background:var(--blue);color:#fff}.secondary-link{background:var(--mist);color:var(--navy)}.quick-strip{margin-top:24px;border:1px solid var(--line);border-radius:14px;padding:16px 20px;background:#fff;display:flex;gap:16px;justify-content:space-between;flex-wrap:wrap}.quick-strip>div{display:flex;flex-wrap:wrap;gap:9px;align-items:center;font-size:13px}.quick-strip strong{color:var(--ink)}.quick-strip a{text-decoration:none;border-bottom:1px solid #a9d2e5}.section-head{max-width:800px;margin-bottom:25px}.section-head p{color:var(--muted)}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:14px}.topic-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:22px;text-decoration:none;display:block;min-width:0}.topic-card:hover{border-color:#8dd8e4;transform:translateY(-2px);box-shadow:0 9px 24px rgba(23,75,120,.06)}.topic-card strong{display:block;color:var(--ink);font-size:18px;margin-bottom:8px}.topic-card p{font-size:14px;color:var(--muted);margin:0;line-height:1.7}.topic-card .arrow{display:block;color:var(--blue);margin-top:12px}.editor-grid{display:grid;grid-template-columns:2fr 1fr;gap:20px}.featured-story{background:var(--mist);border-radius:var(--radius);padding:28px}.featured-story h3{font-size:24px}.stacked-stories{display:grid;gap:16px}.stacked-stories article{background:white;border:1px solid var(--line);border-radius:var(--radius);padding:20px}.split-feature{display:grid;grid-template-columns:1fr 1fr;gap:42px;align-items:center}.split-feature.reverse .media{order:-1}.text-block{max-width:780px}.info-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.info-block{padding:23px;background:#fff;border:1px solid var(--line);border-radius:var(--radius)}.info-block .num{display:block;color:#087a9b;font-size:13px;font-weight:800;margin-bottom:8px}.info-block p{font-size:15px;margin:0}.steps{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:0;counter-reset:step}.steps>div{padding:18px 22px;border-top:3px solid #48b5c9;border-right:1px solid var(--line);background:#fff}.steps>div:last-child{border-right:0}.steps strong{display:block;margin-bottom:8px;color:var(--ink)}.steps p{font-size:14px;margin:0}.content-layout{display:grid;grid-template-columns:minmax(0,780px) minmax(210px,1fr);gap:34px;align-items:start}.article-body{max-width:780px}.article-body h2{margin-top:38px}.article-body h3{margin-top:24px}.article-body ul,.article-body ol{padding-left:23px}.article-body li{margin-bottom:9px}.sidebar{background:var(--mist);padding:23px;border-radius:var(--radius);margin-top:38px}.sidebar dl{margin:0}.sidebar dt{font-weight:700;color:var(--ink);margin-top:14px}.sidebar dd{margin:4px 0 0;font-size:14px}.surface{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:25px}.surface-soft{background:var(--mist);padding:26px;border-radius:var(--radius)}.table-scroll{overflow-x:auto;border:1px solid var(--line);border-radius:12px;background:#fff}table{border-collapse:collapse;width:100%;min-width:540px}th,td{padding:13px 17px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top;font-size:15px}th{background:var(--mist);color:var(--ink);font-weight:700}tr:last-child td{border-bottom:none}.callout{padding:18px 22px;background:var(--mist);border-left:4px solid var(--cyan);border-radius:0 10px 10px 0;margin:22px 0}.callout p:last-child{margin:0}.media{display:flex;align-items:center;justify-content:center;width:100%;min-width:0;overflow:hidden;border-radius:14px;background:var(--mist);border:1px solid var(--line);padding:8px}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media-placeholder{height:100%;width:100%;background:linear-gradient(135deg,#edf8fb,#e6f2f7);border-radius:8px}.media--hero{height:clamp(250px,26vw,330px)}.media--feature{height:250px}.media--card{height:170px}.media--banner{height:220px}.media--mobile{height:350px;max-width:320px}.media.portrait{max-width:360px;margin-inline:auto}.media.panorama{height:auto;min-height:110px;aspect-ratio:3/1}.gallery-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}.gallery-grid figure{margin:0;background:#fff;border:1px solid var(--line);padding:15px;border-radius:var(--radius)}figcaption{font-size:14px;color:var(--muted);margin-top:12px}.gallery-grid figure h3{margin:0 0 5px;font-size:18px}.comparison-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px}.related{border-top:1px solid var(--line);padding-top:26px;margin-top:58px;margin-bottom:54px}.related-links{display:flex;gap:12px;flex-wrap:wrap}.related-links a{border:1px solid var(--line);padding:13px 18px;background:white;border-radius:10px;text-decoration:none;font-weight:700}.faq-list{border-top:1px solid var(--line)}.faq-list details{border-bottom:1px solid var(--line);background:white}.faq-list summary{cursor:pointer;padding:16px 20px;font-weight:700;color:var(--ink)}.faq-list details p{padding:0 20px 16px;margin:0}.mini-nav{display:flex;flex-wrap:wrap;gap:12px;margin:25px 0}.mini-nav a{background:var(--mist);padding:8px 14px;text-decoration:none;border-radius:8px}.editor-note{margin-top:50px;padding:18px 24px;background:#edf4f8;border-left:3px solid var(--navy);font-size:14px}.site-footer{margin-top:65px;background:var(--footer);color:#eaf7ff;padding-top:42px}.footer-grid{display:grid;grid-template-columns:2fr 1fr;gap:80px}.footer-grid p{max-width:600px;font-size:14px;color:#d6ecfa}.footer-brand{font-size:23px;font-weight:800}.footer-brand span{font-size:11px;letter-spacing:2px;margin-left:10px}.footer-grid nav{display:grid;grid-template-columns:repeat(2,1fr);gap:5px 20px;align-content:start}.footer-grid nav strong{grid-column:1/-1}.footer-grid a,.footer-bottom a{color:#eaf7ff}.footer-bottom{display:flex;justify-content:space-between;gap:20px;font-size:13px;border-top:1px solid #45647c;margin-top:28px;padding:15px 0 24px;color:#d6ecfa}@media(max-width:980px){.wrap{width:min(calc(100% - 44px),var(--width))}.topbar{height:64px;justify-content:space-between;gap:10px}.brand img{max-height:30px;max-width:180px}.brand-fallback{font-size:18px}.brand-note,.channel-nav{display:none}.menu-toggle{display:flex;flex-shrink:0}.entry-button{height:40px;min-height:40px;padding:8px 11px;font-size:13px}.drawer-backdrop{display:block;visibility:hidden;opacity:0;pointer-events:none;position:fixed;inset:0;z-index:40;background:rgba(12,36,54,.55);transition:opacity .2s}.mobile-drawer{display:block;visibility:hidden;position:fixed;inset:0 auto 0 0;width:min(86vw,344px);z-index:41;background:white;overflow-y:auto;transform:translateX(-101%);transition:transform .22s,visibility .22s;padding:22px;box-shadow:12px 0 30px rgba(0,0,0,.12)}.drawer-open{overflow:hidden}.drawer-open .drawer-backdrop{visibility:visible;opacity:1;pointer-events:auto}.drawer-open .mobile-drawer{visibility:visible;transform:translateX(0)}.drawer-heading{display:flex;justify-content:space-between;align-items:center;font-size:21px;color:var(--navy);border-bottom:1px solid var(--line);padding-bottom:15px}.drawer-close{border:0;background:var(--mist);border-radius:8px;width:40px;height:40px;color:var(--navy);font-size:26px}.drawer-group{margin-top:22px;display:grid;gap:6px}.drawer-group span{font-size:12px;font-weight:800;color:var(--muted)}.drawer-group a{display:block;text-decoration:none;padding:9px 11px;border-radius:6px}.drawer-group a:hover{background:var(--mist)}.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.mobile-bottom{display:grid;grid-template-columns:repeat(4,1fr);position:fixed;bottom:0;left:0;right:0;z-index:14;background:#fff;border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom)}.mobile-bottom a{text-align:center;text-decoration:none;color:var(--navy);font-size:13px;padding:9px 0}.site-footer{padding-bottom:calc(48px + env(safe-area-inset-bottom))}.back-top{bottom:73px}.content-layout{grid-template-columns:minmax(0,1fr)}.sidebar{margin-top:10px}}@media(max-width:760px){.hero,.split-feature,.editor-grid{grid-template-columns:1fr}.hero{gap:20px}.hero .media{grid-row:1}.split-feature.reverse .media{order:0}.info-grid,.comparison-grid{grid-template-columns:1fr}.steps{grid-template-columns:repeat(2,1fr)}.gallery-grid{grid-template-columns:1fr}.footer-grid{grid-template-columns:1fr;gap:25px}.page-heading{padding-top:30px}}@media(max-width:640px){body{font-size:15px}.wrap{width:calc(100% - 32px)}.topbar{height:62px}.brand img{max-width:135px;max-height:29px}.entry-button{padding:7px 9px;gap:4px}.hero h1{font-size:29px}.hero{padding-top:22px}.hero .lead,.lead{font-size:15px}h1{font-size:27px}h2{font-size:21px}h3{font-size:18px}section{margin-top:36px}.topic-grid{gap:10px}.topic-card{padding:16px}.topic-card strong{font-size:16px}.topic-card p{font-size:13px}.quick-strip{padding:12px}.featured-story,.surface,.surface-soft{padding:19px}.steps>div{padding:15px}.media--hero{height:200px}.media--feature{height:180px}.media--card{height:145px}.media--banner{height:150px}.media--mobile{height:290px;max-width:250px}.related{margin-top:36px}.footer-grid nav{grid-template-columns:repeat(2,1fr)}.footer-bottom{flex-wrap:wrap}.back-top{right:13px}}@media(max-height:420px) and (max-width:980px){.mobile-bottom{position:static}.site-footer{padding-bottom:0}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition-duration:.01ms!important;animation-duration:.01ms!important}}