:root{--bg:#F6FAFC;--surface:#fff;--tint:#EAF6FA;--tint2:#EDF4F8;--cyan:#25C8D1;--sky:#25B6E8;--blue:#1787DB;--navy:#174B78;--title:#183A56;--body:#31485D;--muted:#687D8E;--line:#DCE9F0;--footer:#123653;--max:1180px}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:135px}body{margin:0;background:var(--bg);color:var(--body);font-family:Arial,"PingFang SC","Microsoft YaHei",sans-serif;font-size:16px;line-height:1.8}body.drawer-open{overflow:hidden}a{color:var(--navy);text-underline-offset:4px}a:hover{color:var(--blue)}:focus-visible{outline:3px solid #25B6E8;outline-offset:3px}img{max-width:100%}h1,h2,h3,p{margin-top:0}h1,h2,h3{color:var(--title);line-height:1.38}h1{font-size:clamp(2rem,3.2vw,2.625rem);letter-spacing:-.035em}h2{font-size:clamp(1.4rem,2.1vw,1.7rem);margin-bottom:20px}h3{font-size:1.18rem;margin-bottom:9px}p{margin-bottom:18px}.container{width:min(var(--max),calc(100% - 56px));margin-inline:auto}.section{margin-block:58px}.section-label,.eyebrow{display:block;color:#187F93;text-transform:uppercase;letter-spacing:.13em;font-size:12px;font-weight:800;margin-bottom:12px}.lead{font-size:17px;line-height:1.85;color:#496377;max-width:760px}.muted{color:var(--muted)}.kicker{color:var(--blue);font-weight:700;font-size:14px}.skip-link{position:absolute;top:-100px;left:12px;z-index:200;padding:8px;background:white}.skip-link:focus{top:10px}.site-header{background:#fff;border-bottom:1px solid var(--line);position:relative;z-index:50}.brandbar{height:72px;display:flex;align-items:center;gap:24px}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;max-width:300px;min-width:0}.brand .media{background:transparent}.brand-fallback{font-size:20px;line-height:1.15;font-weight:800;white-space:nowrap;color:var(--title)}.brand-fallback small{display:block;letter-spacing:.12em;font-size:9px;margin-top:3px;color:var(--blue)}.brand:has(img) .brand-fallback{display:none}.brand-subtitle{margin:0 auto;color:var(--muted);font-size:14px;letter-spacing:.12em}.entry-button{display:inline-flex;gap:13px;align-items:center;text-decoration:none;border-radius:9px;padding:9px 22px;background:var(--navy);color:#fff;font-size:14px;font-weight:700;white-space:nowrap}.entry-button:hover{color:#fff;background:#0F3A61}.primary-nav{background:var(--navy)}.nav-links{display:flex;gap:clamp(14px,2.5vw,35px);height:48px;align-items:stretch;justify-content:space-between}.nav-links a{display:flex;align-items:center;color:#D5EDF8;text-decoration:none;font-size:14px;white-space:nowrap;border-bottom:3px solid transparent;padding-top:3px}.nav-links a[aria-current=page]{color:#fff;border-bottom-color:var(--cyan);font-weight:700}.nav-links a:hover{color:#fff}.menu-toggle{display:none}.quickline{border-bottom:1px solid var(--line);background:#f0f8fb}.quickline-inner{display:flex;gap:22px;align-items:center;min-height:46px;flex-wrap:wrap;padding-block:7px;font-size:13px}.quickline-inner span{font-weight:800;color:var(--navy)}.quickline a{text-decoration:none;color:#526A7E}.quickline a:hover{text-decoration:underline}.drawer,.drawer-backdrop{visibility:hidden;pointer-events:none}.mobile-bottom{display:none}main{min-height:50vh}.hero{display:grid;grid-template-columns:1.12fr .88fr;align-items:center;gap:40px;padding-block:48px 18px}.hero h1{max-width:650px;margin-bottom:20px}.hero p{max-width:600px}.hero-actions{display:flex;gap:14px;flex-wrap:wrap;margin-top:25px}.button,.button-ghost{display:inline-flex;padding:11px 19px;align-items:center;border-radius:9px;text-decoration:none;font-weight:700;font-size:14px}.button{color:#fff;background:var(--navy)}.button:hover{color:#fff;background:#0E365A}.button-ghost{border:1px solid #ACCCD9;color:var(--navy)}.button-ghost:hover{background:#e4f5f8}.media{display:flex;align-items:center;justify-content:center;min-width:0;width:100%;overflow:hidden;border-radius:14px;background:var(--tint);border:1px solid var(--line)}.media img{display:block;width:auto;height:auto;max-width:100%;max-height:100%;object-fit:contain;object-position:center}.media-placeholder{width:65%;height:65%;border:1px solid #C6DFE7;border-radius:9px;opacity:.55;background:linear-gradient(135deg,transparent 47%,#d0e7ee 48%,#d0e7ee 52%,transparent 53%)}.media--hero{height:clamp(250px,26vw,330px)}.media--feature{height:250px}.media--card{height:170px}.media--banner{height:220px}.media--inline{height:230px}.media--mobile{height:350px;max-width:320px}.media--portrait{max-width:330px;margin-inline:auto}.media--wide{height:auto;min-height:120px;max-height:240px;aspect-ratio:2.5}.media--logo{height:38px;width:auto;max-width:210px;min-width:125px;border:0;border-radius:0;background:transparent}.media--logo img{max-height:38px}.topic-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px}.topic-card{display:block;padding:23px 21px;background:white;text-decoration:none;border:1px solid var(--line);border-radius:12px;min-width:0;transition:border-color .15s,transform .15s}.topic-card:hover{border-color:#8CCDD9;transform:translateY(-2px)}.topic-card .number{font-size:12px;font-weight:800;color:#1A9CB3}.topic-card h3{margin:7px 0;color:var(--title)}.topic-card p{font-size:14px;color:var(--muted);line-height:1.7;margin:0}.topic-card .arrow{display:block;text-align:right;color:var(--blue);font-size:20px}.split-feature{display:grid;grid-template-columns:2fr 1fr;gap:20px}.feature-main{padding:32px;background:var(--tint);border-radius:14px}.feature-main p{max-width:670px}.feature-side{display:grid;gap:15px}.note-panel{background:#fff;border:1px solid var(--line);padding:23px;border-radius:13px}.note-panel p{margin-bottom:12px}.text-link{font-size:14px;font-weight:700;text-decoration-thickness:1px}.editorial-row{display:grid;grid-template-columns:1fr 1fr;align-items:center;gap:45px}.editorial-row.reverse .media{order:2}.editorial-row.reverse .editorial-text{order:1}.editorial-text{max-width:575px}.mini-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.mini-grid>article{padding:24px;border-top:3px solid #25C8D1;background:white;border-radius:0 0 10px 10px}.mini-grid p{font-size:15px;margin:0}.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:13px;counter-reset:step}.step{padding:19px;border:1px solid var(--line);background:white;border-radius:10px}.step strong{display:block;color:var(--title)}.step small{display:block;color:#148AA0;font-weight:700}.editor-note{padding:22px 27px;border-left:4px solid var(--cyan);background:var(--tint2);font-size:14px}.page-hero{padding-top:45px;padding-bottom:15px}.page-hero h1{font-size:clamp(2rem,2.9vw,2.25rem);margin-bottom:16px}.page-hero .lead{margin:0}.content-section{margin-block:48px}.content-section p{max-width:790px}.paper{background:#fff;border:1px solid var(--line);border-radius:14px;padding:28px}.paper h3{margin-top:5px}.columns-2{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:22px}.columns-3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:19px}.numbered{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px}.numbered>article{padding:24px;background:var(--tint2);border-radius:12px}.num{color:#0F8BA5;font-size:29px;font-weight:800;line-height:1.2;display:block;margin-bottom:12px}.table-wrap{max-width:100%;overflow-x:auto;border:1px solid var(--line);border-radius:12px;background:#fff}table{width:100%;border-collapse:collapse;text-align:left;min-width:580px}th,td{padding:15px 18px;border-bottom:1px solid var(--line);vertical-align:top;font-size:14px;line-height:1.7}th{background:var(--tint2);color:var(--title);font-weight:800}tr:last-child td{border-bottom:0}.article-with-aside{display:grid;grid-template-columns:minmax(0,760px) minmax(0,240px);gap:45px;align-items:start}.article-with-aside .content-section:first-child{margin-top:0}.aside-box{padding:22px;background:#EAF6FA;border-radius:12px;position:sticky;top:20px}.aside-box dl{margin:0}.aside-box dt{font-weight:800;color:var(--title);margin-top:17px}.aside-box dd{margin:0;font-size:14px}.inline-list{padding-left:21px;max-width:790px}.inline-list li{margin-bottom:10px}.outline-nav{display:flex;flex-wrap:wrap;gap:10px;margin:20px 0}.outline-nav a{background:#EAF6FA;padding:7px 13px;border-radius:7px;text-decoration:none;font-size:14px;font-weight:700}.callout{background:#EAF6FA;border-radius:12px;padding:21px 26px}.gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px}.gallery figure{margin:0;background:#fff;border:1px solid var(--line);border-radius:13px;padding:15px}.gallery figcaption{font-size:14px;padding:14px 6px 4px;line-height:1.7}.gallery figcaption strong{display:block;color:var(--title);font-size:17px;margin-bottom:3px}.faq-list{border-top:1px solid var(--line)}.faq-list details{border-bottom:1px solid var(--line);background:#fff}.faq-list summary{padding:19px 22px;cursor:pointer;color:var(--title);font-weight:700;list-style-position:inside}.faq-list details p{padding:0 23px 20px;margin:0;font-size:15px;max-width:900px}.related-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.related-link{background:white;border:1px solid var(--line);border-radius:11px;text-decoration:none;display:grid;grid-template-columns:1fr auto;padding:22px;gap:5px}.related-link strong{grid-column:1;color:var(--title)}.related-link span:nth-child(2){grid-column:1;font-size:13px;color:var(--muted)}.related-link span:last-child{grid-column:2;grid-row:1/3;color:var(--blue)}.site-footer{background:var(--footer);color:#D8E8F3;margin-top:80px;padding-top:52px;font-size:14px}.footer-layout{display:grid;grid-template-columns:1.2fr 1.15fr 1fr;gap:50px}.site-footer h2{color:#fff;font-size:16px}.site-footer a{color:#D7F4FA}.footer-brand{font-size:22px;color:#fff;font-weight:800;margin-bottom:14px}.footer-brand span{display:block;font-size:10px;letter-spacing:.14em;color:#8ED6E9}.footer-note{font-size:13px;color:#B7D3E2}.footer-links{display:grid;grid-template-columns:1fr 1fr;gap:8px 15px}.footer-bottom{display:flex;justify-content:space-between;border-top:1px solid #37607B;margin-top:40px;padding:17px 0;color:#B8D2E0}.back-top{position:fixed;bottom:20px;right:20px;border:0;background:var(--navy);color:#fff;border-radius:50%;width:43px;height:43px;font-size:19px;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .2s;cursor:pointer;z-index:20}.back-top.visible{visibility:visible;opacity:1;pointer-events:auto}
@media(max-width:980px){.container{width:calc(100% - 44px)}.primary-nav{display:none}.brandbar{height:64px;justify-content:space-between;gap:10px}.brand-subtitle{display:none}.menu-toggle{display:flex;width:40px;height:40px;flex:0 0 40px;align-items:center;justify-content:center;flex-direction:column;gap:5px;background:#EDF6F9;border:1px solid var(--line);border-radius:8px;cursor:pointer}.menu-toggle span{width:17px;height:2px;background:var(--title)}.brand{margin:auto}.brand .media--logo{height:30px;max-width:140px;min-width:70px}.brand .media--logo img{max-height:30px}.brand-fallback{font-size:17px}.entry-button{padding:9px 11px;font-size:12px;min-height:39px}.entry-button span{display:none}.drawer-backdrop{position:fixed;inset:0;background:rgba(9,37,55,.5);z-index:90;opacity:0;transition:opacity .2s}.drawer{position:fixed;z-index:91;top:0;bottom:0;left:0;width:min(86vw,344px);background:#fff;overflow-y:auto;transform:translateX(-101%);transition:transform .22s;box-shadow:10px 0 40px rgba(0,0,0,.08);padding:20px}.drawer-open .drawer,.drawer-open .drawer-backdrop{visibility:visible;pointer-events:auto}.drawer-open .drawer{transform:translateX(0)}.drawer-open .drawer-backdrop{opacity:1}.drawer-top{display:flex;align-items:center;justify-content:space-between;color:var(--title);font-weight:800;font-size:19px}.drawer-close{background:#EAF6FA;border:0;border-radius:7px;color:var(--title);font-size:27px;width:40px;height:40px;cursor:pointer}.drawer-group{padding:18px 0;border-bottom:1px solid var(--line)}.drawer-group h2{font-size:13px;color:var(--muted);letter-spacing:.08em;margin:0 0 9px}.drawer-group a{display:block;padding:8px 5px;text-decoration:none;font-size:16px;font-weight:700}.topic-grid{grid-template-columns:repeat(3,1fr)}.article-with-aside{grid-template-columns:minmax(0,1fr) 210px;gap:22px}.footer-layout{gap:25px}}
@media(max-width:760px){.hero,.editorial-row,.split-feature,.columns-2,.article-with-aside{grid-template-columns:1fr}.hero{gap:20px;padding-top:30px}.hero .media{order:-1}.editorial-row.reverse .media{order:initial}.editorial-row.reverse .editorial-text{order:initial}.feature-side{grid-template-columns:1fr 1fr}.topic-grid,.columns-3,.numbered,.related-grid{grid-template-columns:repeat(2,1fr)}.aside-box{position:static}.footer-layout{grid-template-columns:1fr 1fr}.footer-layout>div:first-child{grid-column:1/-1}.steps{grid-template-columns:repeat(2,1fr)}.quickline-inner{gap:8px 16px}.quickline-inner span{display:none}}
@media(max-width:640px){body{font-size:15px}.container{width:calc(100% - 32px)}h1{font-size:29px}.page-hero h1{font-size:27px}h2{font-size:22px}h3{font-size:18px}.lead{font-size:15px}.section{margin-block:36px}.content-section{margin-block:34px}.page-hero{padding-top:30px}.topic-grid,.columns-3,.numbered,.mini-grid,.related-grid,.gallery,.feature-side,.footer-layout{grid-template-columns:1fr}.topic-card{padding:18px}.paper,.feature-main{padding:21px}.hero{gap:22px}.hero-actions{gap:9px}.button,.button-ghost{padding:10px 12px}.media--hero{height:200px}.media--feature{height:180px}.media--card{height:145px}.media--banner{height:150px}.media--inline{height:185px}.media--mobile{height:290px;max-width:250px}.media--wide{height:auto;min-height:100px}.site-footer{margin-top:50px;padding:36px 0 80px}.footer-layout>div:first-child{grid-column:auto}.footer-bottom{gap:10px;flex-wrap:wrap}.mobile-bottom{display:grid;grid-template-columns:repeat(4,1fr);position:fixed;bottom:0;left:0;right:0;z-index:40;background:#fff;border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom);box-shadow:0 -4px 20px rgba(0,0,0,.04)}.mobile-bottom a{text-align:center;padding:10px 0;color:var(--body);font-size:13px;font-weight:700;text-decoration:none}.mobile-bottom a[aria-current=page]{color:#087F9A;border-top:3px solid var(--cyan);padding-top:7px}.back-top{bottom:65px}.entry-button{padding-inline:9px}.brand-fallback small{font-size:8px}.quickline-inner{padding-block:9px;gap:5px 13px;line-height:1.35}}
@media(max-height:480px) and (max-width:640px){.mobile-bottom{position:static}.site-footer{padding-bottom:25px}.back-top{bottom:15px}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{scroll-behavior:auto!important;transition:none!important;animation:none!important}}