*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:#F4F7FA;color:#344C60;font:16px/1.8 Arial,"PingFang SC","Microsoft YaHei",sans-serif}img{display:block;max-width:100%}a{color:#1766a2;text-underline-offset:3px}a:hover{color:#0c7188}button{font:inherit;cursor:pointer}h1,h2,h3{line-height:1.38;color:#18364B;margin:0 0 .75em}h1{font-size:clamp(27px,3.2vw,42px)}h2{font-size:clamp(21px,2.3vw,27px)}h3{font-size:19px}p{margin:.5em 0 1.2em}ul,ol{padding-left:1.45em}li{margin-bottom:.5em}section{scroll-margin-top:20px}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid #13B8C5;outline-offset:3px}.container{width:min(100% - 56px,1200px);margin-inline:auto}.section{margin-block:56px}.muted{color:#64798A}.lead{font-size:17px;line-height:1.86;max-width:790px}.eyebrow{text-transform:uppercase;letter-spacing:.15em;color:#167e8d;font-size:12px;font-weight:700}.site-header{background:#fff}.brand-bar{min-height:72px;display:flex;align-items:center;justify-content:space-between;gap:24px}.brand-identity{display:flex;gap:22px;align-items:center;min-width:0}.brand-tag{color:#64798A;font-size:13px}.brand-logo,.mobile-logo{display:flex;align-items:center}.logo-frame{padding:0;margin:0;background:transparent;max-width:220px}.logo-frame img{width:auto;height:auto;max-height:38px;object-fit:contain}.logo-frame.media-missing{min-height:34px;min-width:110px;background:#EAF1F6;color:#163C57;font-size:12px}.register-btn,.solid-link{display:inline-flex;align-items:center;justify-content:center;background:#163C57;color:#fff;text-decoration:none;font-weight:700;padding:8px 20px;border-radius:10px;white-space:nowrap}.register-btn:hover,.solid-link:hover{color:#fff;background:#216181}.desktop-nav{background:#102E46}.nav-line{display:flex;align-items:stretch;justify-content:space-between;gap:8px;min-height:50px}.nav-line a{display:flex;align-items:center;justify-content:center;position:relative;white-space:nowrap;padding:6px 14px;color:#eaf1f6;text-decoration:none;font-size:15px}.nav-line a[aria-current="page"]{font-weight:700;color:#fff}.nav-line a[aria-current="page"]:after{content:"";position:absolute;height:3px;background:#13B8C5;bottom:0;left:22%;right:22%}.mobile-header,.mobile-drawer,.drawer-overlay,.mobile-quick,.nojs-nav{display:none}.skip-link{position:absolute;top:-100px;left:15px;z-index:99;background:#fff;padding:6px 10px}.skip-link:focus{top:10px}.breadcrumb{display:flex;gap:10px;align-items:center;color:#64798A;font-size:14px;margin-top:23px}.page-intro{padding:39px 0 18px;border-bottom:1px solid #DCE6ED}.page-intro h1{font-size:clamp(25px,3vw,36px)}.page-intro .lead{margin-bottom:18px}.topic-nav{display:flex;flex-wrap:wrap;gap:10px;padding:15px 0}.topic-nav a{padding:7px 16px;border:1px solid #C9DCE8;border-radius:30px;text-decoration:none;background:#fff;font-size:14px}.section-heading{border-top:3px solid #13B8C5;padding-top:16px;max-width:800px}.hero{display:grid;grid-template-columns:52fr 48fr;gap:30px;align-items:center;margin-top:35px}.hero-copy h1{max-width:590px}.hero-actions,.related-links{display:flex;flex-wrap:wrap;gap:12px}.text-link{display:inline-block;font-weight:700;padding:8px 0}.media-frame{display:flex;align-items:center;justify-content:center;min-width:0;width:100%;margin:0;background:#EAF1F6;border-radius:14px;padding:9px}.media-frame img{width:auto;height:auto;max-width:100%;max-height:var(--media-limit,220px);object-fit:contain;object-position:center}.media-frame--hero{--media-limit:310px}.media-frame--feature{--media-limit:250px}.media-frame--card{--media-limit:185px}.media-frame--wide{--media-limit:210px}.media-frame--mobile{--media-limit:350px;max-width:320px;margin:auto}.media-missing{min-height:110px;color:#64798A;font-size:13px;text-align:center}.topic-index{display:grid;grid-template-columns:1fr 1fr;gap:0 40px}.topic-index article{border-top:1px solid #DCE6ED;padding:18px 2px}.topic-index h3{margin-bottom:4px}.topic-index p{margin:0 0 7px}.focus-grid{display:grid;grid-template-columns:2fr 1fr;gap:34px}.feature-article{padding:29px;background:#fff;border-left:4px solid #13B8C5}.brief-stack{display:grid;gap:20px}.brief-stack article{border-bottom:1px solid #DCE6ED;padding:12px 0}.split{display:grid;grid-template-columns:1fr 1fr;gap:36px;align-items:center}.split.wide-text{grid-template-columns:.8fr 1.2fr}.surface{background:#fff;border:1px solid #DCE6ED;border-radius:12px;padding:23px}.soft{background:#EAF1F6;padding:28px;border-radius:12px}.tint{background:#E9F8F8;padding:28px;border-radius:12px}.reading-steps{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;counter-reset:route}.reading-steps article{border-top:3px solid #237BD3;padding:12px 8px}.reading-steps article:before{counter-increment:route;content:'0' counter(route);font-size:26px;color:#237BD3;font-weight:700}.editor-note{padding:22px 26px;border-left:4px solid #13B8C5;background:#E9F8F8}.content-grid{display:grid;grid-template-columns:minmax(0,2fr) minmax(225px,.78fr);gap:44px;align-items:start}.article-body{max-width:790px}.article-body section{margin-bottom:48px}.info-aside{background:#EAF1F6;border-radius:12px;padding:23px}.info-aside h2{font-size:20px}.steps{list-style:none;counter-reset:step;padding:0}.steps li{counter-increment:step;border-left:2px solid #13B8C5;padding:1px 0 20px 28px;position:relative}.steps li:before{content:counter(step);position:absolute;left:-16px;top:1px;display:grid;place-items:center;width:30px;height:30px;border-radius:50%;background:#163C57;color:#fff;font-weight:700}.steps li strong{display:block;color:#18364B}.table-scroll{overflow-x:auto;background:#fff;border:1px solid #DCE6ED;border-radius:12px}.data-table{border-collapse:collapse;width:100%;min-width:620px;font-size:15px}.data-table caption{text-align:left;font-weight:700;padding:17px;color:#18364B}.data-table th,.data-table td{border-bottom:1px solid #DCE6ED;padding:13px 17px;text-align:left;vertical-align:top}.data-table th{background:#EAF1F6;color:#18364B}.data-table tr:last-child td{border-bottom:0}.three{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}.three>article{padding:20px;background:#fff;border-top:3px solid #13B8C5}.contrast-band{background:#163C57;color:#DCECF5;padding:30px;border-radius:12px}.contrast-band h2,.contrast-band h3{color:white}.related{border-top:1px solid #DCE6ED;padding-top:22px}.related-links a{background:#fff;border:1px solid #DCE6ED;border-radius:8px;padding:10px 16px;text-decoration:none}.term-list{display:grid;grid-template-columns:1fr 1fr;gap:18px}.term-list>div{border-bottom:1px solid #DCE6ED;padding:15px 0}.term-list dt{font-weight:700;color:#18364B}.term-list dd{margin:0}.exhibit{display:grid;grid-template-columns:1fr 1.15fr;gap:30px;align-items:center;margin-block:30px}.exhibit:nth-child(even){grid-template-columns:1.15fr 1fr}.rule-layout{display:grid;grid-template-columns:220px minmax(0,1fr);gap:42px}.rule-side{position:sticky;top:20px;align-self:start;background:#fff;border:1px solid #DCE6ED;padding:20px;border-radius:12px}.rule-side a{display:block;margin:8px 0}.faq-list details{border-bottom:1px solid #DCE6ED;background:#fff;padding:0 17px}.faq-list summary{font-weight:700;color:#18364B;cursor:pointer;padding:15px 0}.faq-list details p{padding:0 0 14px}.about-layout{display:grid;grid-template-columns:220px minmax(0,1fr);gap:40px}.about-side{background:#EAF1F6;border-radius:12px;padding:19px;height:max-content}.about-side a{display:block;margin:8px 0}.site-footer{background:#0B2539;color:#DCECF5;margin-top:50px;padding:38px 0 15px}.site-footer h2{color:#fff;font-size:19px}.site-footer a{color:#DCECF5}.footer-grid{display:grid;grid-template-columns:1.4fr .6fr;gap:45px}.footer-brand{display:flex;align-items:center;gap:12px}.footer-links{display:grid;grid-template-columns:1fr 1fr;gap:5px 16px}.footer-bottom{border-top:1px solid #325069;padding-top:15px;margin-top:23px;font-size:13px}.site-footer .logo-frame{max-width:140px}.site-footer .logo-frame img{max-height:30px}#back-top{position:fixed;bottom:20px;right:20px;border:0;background:#163C57;color:#fff;padding:8px 15px;border-radius:10px;z-index:5}#back-top[hidden]{display:none}
@media(max-width:1024px){.container{width:calc(100% - 44px)}.nav-line a{padding-inline:8px;font-size:14px}.section{margin-block:44px}.split,.focus-grid{gap:24px}}
@media(max-width:920px){.brand-bar,.desktop-nav{display:none}.mobile-header{height:64px;padding:0 22px;display:grid;grid-template-columns:44px minmax(0,1fr) auto;align-items:center;gap:10px}.mobile-logo{justify-self:center;min-width:0}.mobile-logo .logo-frame img{max-height:30px}.mobile-header .register-btn{height:39px;padding:5px 11px;font-size:13px}.menu-toggle{border:0;background:transparent;width:40px;height:40px;display:flex;flex-direction:column;justify-content:center;gap:5px;align-items:center}.menu-toggle span{display:block;width:21px;height:2px;background:#102E46}.drawer-overlay{display:block;position:fixed;inset:0;background:rgba(5,25,39,.54);z-index:30;visibility:hidden;opacity:0;pointer-events:none;transition:opacity .18s,visibility .18s}.drawer-overlay.is-open{visibility:visible;opacity:1;pointer-events:auto}.mobile-drawer{display:block;position:fixed;inset:0 auto 0 0;width:min(86vw,340px);background:#fff;z-index:31;padding:19px 22px;overflow-y:auto;transform:translateX(-105%);visibility:hidden;transition:transform .2s,visibility .2s}.mobile-drawer.is-open{transform:translateX(0);visibility:visible}.mobile-drawer>a{display:block;text-decoration:none;border-bottom:1px solid #DCE6ED;padding:10px 4px;color:#18364B}.drawer-top{display:flex;justify-content:space-between;align-items:center}.drawer-top button{border:0;background:#EAF1F6;border-radius:8px;width:40px;height:40px;font-size:28px}.drawer-heading{font-size:13px;font-weight:700;color:#64798A;margin:23px 0 0}.drawer-active{overflow:hidden}.mobile-quick{display:flex;flex-wrap:wrap;gap:12px;padding-block:20px;border-top:1px solid #DCE6ED;margin-top:36px}.mobile-quick a{font-size:14px}.nojs-nav{display:flex;flex-wrap:wrap;gap:7px;padding:12px 0}.nojs-nav a{padding:5px 9px;background:#fff;border-radius:6px}}
@media(max-width:760px){.hero,.focus-grid,.split,.split.wide-text,.content-grid,.rule-layout,.about-layout,.exhibit,.exhibit:nth-child(even){grid-template-columns:1fr}.hero{margin-top:22px}.hero .media-frame{grid-row:2}.topic-index,.term-list{grid-template-columns:1fr}.three{grid-template-columns:1fr}.reading-steps{grid-template-columns:1fr 1fr}.about-layout main{grid-row:1}.about-side{grid-row:2}.rule-side{position:static}.footer-grid{grid-template-columns:1fr}.exhibit:nth-child(even) .media-frame{grid-row:1}.section{margin-block:39px}}
@media(max-width:640px){body{font-size:15px;line-height:1.76}.container{width:calc(100% - 32px)}h1{font-size:29px}h2{font-size:22px}h3{font-size:18px}.mobile-header{padding-inline:16px}.section{margin-block:33px}.lead{font-size:16px}.page-intro{padding-top:24px}.media-frame--hero{--media-limit:205px}.media-frame--feature{--media-limit:185px}.media-frame--card{--media-limit:145px}.media-frame--wide{--media-limit:135px}.media-frame--mobile{--media-limit:285px;max-width:250px}.reading-steps{grid-template-columns:1fr}.surface,.soft,.tint{padding:17px}.feature-article{padding:19px}.contrast-band{padding:20px}.hero-actions{gap:9px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{transition:none!important;animation:none!important}}
