:root{--bg:#F4F7FA;--white:#fff;--soft:#EAF1F6;--mint:#E9F8F8;--nav:#102E46;--nav2:#163C57;--teal:#13B8C5;--blue:#237BD3;--title:#18364B;--text:#344C60;--muted:#64798A;--line:#DCE6ED;--footer:#0B2539;--gutter:28px}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:var(--bg);color:var(--text);font-family:Arial,"PingFang SC","Microsoft YaHei",sans-serif;font-size:16px;line-height:1.8;overflow-wrap:break-word}a{color:#1769ad;text-decoration:none}a:hover{text-decoration:underline}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--teal);outline-offset:3px}button{font:inherit;cursor:pointer}.wrap{max-width:1200px;margin:0 auto;padding-left:var(--gutter);padding-right:var(--gutter)}h1,h2,h3{color:var(--title);line-height:1.38;margin:0 0 17px}h1{font-size:clamp(32px,3.3vw,36px);letter-spacing:-.025em}h2{font-size:clamp(24px,2.25vw,28px)}h3{font-size:20px}p{margin:0 0 18px}ul,ol{padding-left:1.5em}li{margin-bottom:7px}small,.small{font-size:13px}section{scroll-margin-top:28px}.section{margin:56px auto}.article-width{max-width:800px}.eyebrow{display:block;color:#168791;font-size:13px;font-weight:800;letter-spacing:.13em;text-transform:uppercase;margin-bottom:10px}.lede{font-size:18px;line-height:1.8;color:#405f72;max-width:790px}.section-head{max-width:820px;margin-bottom:25px}.muted{color:var(--muted)}.skip-link{position:absolute;top:-100px;left:10px;background:white;padding:10px;z-index:100}.skip-link:focus{top:10px}
.site-header{position:relative;z-index:20}.brand-bar{background:white;border-bottom:1px solid var(--line)}.brand-inner{min-height:72px;display:flex;align-items:center;gap:22px}.brand{display:inline-flex;align-items:center;justify-content:center;flex:0 1 auto;min-width:0}.brand-logo{display:block;width:auto;height:auto;max-height:38px;max-width:min(240px,100%);object-fit:contain}.brand-word{font-size:23px;line-height:1.1;font-weight:800;white-space:nowrap;color:var(--nav)}.brand-word small{display:block;font-size:9px;letter-spacing:.15em;color:#34728a;margin-top:4px}.brand-desc{color:var(--muted);font-size:13px;white-space:nowrap}.entry-btn{margin-left:auto;display:inline-flex;align-items:center;justify-content:center;min-height:40px;padding:7px 23px;white-space:nowrap;border-radius:8px;background:var(--nav);color:white;font-weight:700;font-size:14px}.entry-btn:hover{background:#1e506c;text-decoration:none}.desktop-nav{background:var(--nav)}.nav-inner{min-height:50px;display:grid;grid-template-columns:repeat(7,minmax(0,1fr));align-items:stretch}.nav-inner a{min-width:0;display:flex;align-items:center;justify-content:center;text-align:center;white-space:nowrap;color:#dcecf5;font-size:14px;font-weight:600;position:relative;padding:10px 3px}.nav-inner a:hover,.nav-inner a[aria-current=page]{color:white;text-decoration:none;background:#193f58}.nav-inner a[aria-current=page]::after{content:"";position:absolute;bottom:0;left:35%;width:30%;height:3px;background:var(--teal)}.menu-toggle,.mobile-drawer,.drawer-overlay{display:none}.noscript-nav{background:#e9f8f8}.noscript-nav .wrap{display:flex;gap:15px;flex-wrap:wrap;padding-top:9px;padding-bottom:9px}
.hero{background:white;border-bottom:1px solid var(--line)}.hero-inner{display:grid;grid-template-columns:minmax(0,1.08fr) minmax(0,1fr);align-items:center;gap:35px;padding-top:46px;padding-bottom:46px}.hero h1{font-size:clamp(38px,3.5vw,44px)}.hero .lede{font-size:17px}.actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:26px}.btn{display:inline-flex;align-items:center;justify-content:center;font-size:14px;line-height:1.5;font-weight:800;min-height:43px;padding:9px 18px;border-radius:8px;background:var(--nav);color:white}.btn:hover{text-decoration:none;background:#27526d}.btn-secondary{background:var(--mint);color:var(--nav);border:1px solid #a7dadd}.btn-secondary:hover{background:#d4efef}.media-frame{display:flex;align-items:center;justify-content:center;width:100%;min-width:0;max-width:100%;margin:0;padding:8px;background:var(--soft);border-radius:14px;overflow:hidden}.media-frame img{display:block;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--banner{--media-limit:210px}.media-frame--mobile{--media-limit:350px;max-width:320px}.media-frame--missing{min-height:116px;border:1px dashed #c4d5e0;color:#748b9b;font-size:13px;text-align:center}.media-frame--missing.media-frame--hero{min-height:205px}.media-frame--missing.media-frame--mobile{min-height:180px}
.page-intro{padding-top:42px;padding-bottom:27px}.page-intro p{max-width:800px}.breadcrumbs{display:flex;gap:8px;flex-wrap:wrap;color:var(--muted);font-size:13px;margin-bottom:18px}.breadcrumbs a{color:var(--muted)}.prose{max-width:800px}.prose p{line-height:1.82}.prose h2{margin-top:35px}.anchor-nav{display:flex;align-items:center;flex-wrap:wrap;gap:9px;padding:13px 17px;background:white;border:1px solid var(--line);border-radius:12px;margin:5px auto 36px}.anchor-nav strong{font-size:13px;color:var(--title);margin-right:9px}.anchor-nav a{font-size:14px;background:var(--soft);padding:5px 12px;border-radius:6px}.editor-grid{display:grid;grid-template-columns:minmax(0,2fr) minmax(0,1fr);gap:22px;align-items:start}.editor-grid>*{min-width:0}.surface{background:white;border:1px solid var(--line);border-radius:13px;padding:26px}.soft-surface{background:var(--soft);border-radius:13px;padding:25px}.mint-surface{background:var(--mint);border-radius:13px;padding:25px}.dark-surface{background:var(--nav2);color:#e5f2f6;border-radius:13px;padding:27px}.dark-surface h2,.dark-surface h3,.dark-surface a{color:white}.dark-surface .eyebrow{color:#65e1e5}.dark-surface p{color:#d4e7ef}.topic-index{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 30px;border-top:1px solid var(--line)}.topic-row{border-bottom:1px solid var(--line);padding:21px 0}.topic-row span{font-size:12px;font-weight:700;color:#0a939c}.topic-row h3{font-size:19px;margin:6px 0}.topic-row p{font-size:15px;margin:0}.topic-row a{color:var(--title)}.feature-split{display:grid;grid-template-columns:minmax(0,.88fr) minmax(0,1.12fr);gap:35px;align-items:center}.feature-split>*{min-width:0}.feature-split.reverse{grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr)}.feature-split.reverse .media-frame{order:2}.triplet{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px}.triplet>*{min-width:0}.step-list{list-style:none;counter-reset:step;padding:0;display:grid;gap:13px}.step-list li{counter-increment:step;position:relative;padding:18px 18px 18px 66px;background:white;border:1px solid var(--line);border-radius:10px;margin:0}.step-list li::before{content:counter(step,decimal-leading-zero);position:absolute;left:19px;top:17px;color:#007f8b;font-size:21px;font-weight:800}.step-list li strong{display:block;color:var(--title)}.thin-rule{border:0;border-top:1px solid var(--line);margin:25px 0}.side-index{font-size:14px}.side-index a{display:block;border-bottom:1px solid var(--line);padding:9px 0}.side-index strong{color:var(--title)}.table-scroll{max-width:100%;overflow-x:auto;border:1px solid var(--line);border-radius:10px;background:#fff}.table-scroll table{width:100%;border-collapse:collapse;min-width:570px;text-align:left}.table-scroll caption{text-align:left;padding:17px 19px 8px;font-weight:700;color:var(--title)}th,td{padding:12px 15px;vertical-align:top;border-bottom:1px solid var(--line)}th{background:#EAF1F6;font-size:14px;color:var(--title)}td{font-size:15px}.table-scroll tr:last-child td{border-bottom:0}.list-card{border-left:3px solid var(--teal);padding:9px 0 10px 18px;margin-bottom:19px}.list-card h3{margin-bottom:6px}.quote{border-left:4px solid var(--teal);background:#effafa;padding:20px 25px;font-size:18px;line-height:1.7;color:var(--title)}.reading-path{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px}.reading-path>a{background:white;border:1px solid var(--line);border-radius:10px;padding:20px 16px;color:var(--title);font-weight:700}.reading-path>a span{display:block;color:#168791;font-size:13px}.reading-path>a:hover{text-decoration:none;border-color:var(--teal)}.exhibit{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px;align-items:start}.exhibit>*{min-width:0}.exhibit article:nth-child(even){margin-top:45px}.exhibit article{background:white;border:1px solid var(--line);border-radius:14px;padding:18px}.exhibit h3{margin:18px 0 8px}.rules-body{max-width:820px}.faq{background:#fff;border:1px solid var(--line);border-radius:9px;margin:10px 0;padding:0 18px}.faq summary{cursor:pointer;font-size:16px;font-weight:700;color:var(--title);padding:14px 0}.faq p{padding:0 0 15px;margin:0;color:var(--text)}.about-layout{display:grid;grid-template-columns:minmax(0,240px) minmax(0,1fr);gap:35px;align-items:start}.about-layout>*{min-width:0}.about-layout .side-index{position:sticky;top:20px}.related-links{display:flex;flex-wrap:wrap;gap:10px;margin-top:20px}.related-links a{background:#fff;border:1px solid var(--line);padding:9px 14px;border-radius:8px;font-size:14px}.related-links a:hover{border-color:var(--teal)}.mobile-quick{display:none}.site-footer{background:var(--footer);color:#dcecf5;padding-top:42px}.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:35px;padding-bottom:33px}.footer-grid>*{min-width:0}.footer-grid p{font-size:14px;max-width:500px;color:#dcecf5}.footer-grid nav{display:flex;flex-direction:column;gap:6px;font-size:14px}.footer-grid nav strong{margin-bottom:6px;color:#fff}.footer-grid a{color:#dcecf5}.footer-brand{display:inline-flex;margin-bottom:15px}.footer-brand .brand-word{color:white}.footer-bottom{border-top:1px solid #285069;padding-top:15px;padding-bottom:21px;font-size:13px;color:#dcecf5}.back-top{position:fixed;right:20px;bottom:20px;z-index:15;display:grid;place-items:center;width:42px;height:42px;border:0;border-radius:50%;background:var(--nav);color:white;font-size:24px;box-shadow:0 3px 15px #18364b44}.back-top[hidden]{display:none}
@media(max-width:1200px){:root{--gutter:22px}}@media(max-width:920px){.brand-inner{min-height:62px;display:grid;grid-template-columns:40px minmax(0,1fr) auto;gap:9px}.brand{justify-self:center;width:100%}.brand-logo{max-height:30px;max-width:min(190px,100%)}.brand-word{font-size:19px}.brand-word small{font-size:8px}.brand-desc,.desktop-nav{display:none}.entry-btn{min-height:39px;padding:7px 12px;font-size:12px}.menu-toggle{display:flex;flex-direction:column;justify-content:center;align-items:center;gap:5px;width:40px;height:40px;padding:8px;border:1px solid var(--line);background:white;border-radius:8px}.menu-toggle span{display:block;width:19px;height:2px;background:var(--nav)}.drawer-overlay{display:block;position:fixed;inset:0;background:rgba(9,32,47,.54);z-index:30;opacity:0;visibility:hidden;pointer-events:none;transition:opacity .2s,visibility .2s}.mobile-drawer{display:block;position:fixed;inset:0 auto 0 0;width:min(86vw,340px);max-height:100dvh;overflow-y:auto;background:#fff;z-index:31;transform:translateX(-105%);visibility:hidden;transition:transform .2s,visibility .2s;box-shadow:8px 0 30px #102e4620}.drawer-open{overflow:hidden}.drawer-open .drawer-overlay{opacity:1;visibility:visible;pointer-events:auto}.drawer-open .mobile-drawer{transform:translateX(0);visibility:visible}.drawer-heading{display:flex;justify-content:space-between;align-items:center;padding:12px 20px;border-bottom:1px solid var(--line);color:var(--title)}.drawer-close{border:0;background:var(--soft);border-radius:8px;width:40px;height:40px;font-size:28px;line-height:1}.drawer-group{padding:14px 22px 8px}.drawer-group h2{font-size:13px;color:var(--muted);margin:0 0 8px}.drawer-group a{display:block;padding:10px 8px;color:var(--title);border-bottom:1px solid var(--line);font-size:16px}.drawer-group a[aria-current=page]{font-weight:800;border-left:3px solid var(--teal);padding-left:12px}.mobile-quick{display:flex;flex-wrap:wrap;justify-content:center;gap:12px;padding-top:15px;padding-bottom:15px;font-size:13px}.hero-inner{gap:20px}}
@media(max-width:760px){.hero-inner,.editor-grid,.feature-split,.feature-split.reverse,.about-layout{grid-template-columns:minmax(0,1fr)}.feature-split.reverse .media-frame{order:0}.triplet{grid-template-columns:minmax(0,1fr) minmax(0,1fr)}.reading-path{grid-template-columns:repeat(2,minmax(0,1fr))}.about-layout .side-index{position:static;order:2}.footer-grid{grid-template-columns:1.5fr 1fr;gap:20px}.footer-grid>div:first-child{grid-column:1/-1}.hero-inner{padding-top:33px;padding-bottom:34px}.section{margin-top:42px;margin-bottom:42px}}
@media(max-width:640px){:root{--gutter:16px}body{font-size:15px}h1{font-size:clamp(25px,6.7vw,29px)}h2{font-size:clamp(20px,5.4vw,23px)}h3{font-size:18px}.hero h1{font-size:clamp(27px,7.5vw,32px)}.hero-inner{gap:23px}.hero .lede,.lede{font-size:16px}.page-intro{padding-top:29px}.section{margin-top:33px;margin-bottom:33px}.surface,.soft-surface,.mint-surface,.dark-surface{padding:18px}.topic-index,.exhibit,.triplet{grid-template-columns:minmax(0,1fr)}.exhibit article:nth-child(even){margin-top:0}.media-frame--hero{--media-limit:205px}.media-frame--feature{--media-limit:185px}.media-frame--card{--media-limit:145px}.media-frame--banner{--media-limit:135px}.media-frame--mobile{--media-limit:285px;max-width:250px;margin:0 auto}.anchor-nav{gap:6px;padding:11px}.anchor-nav a{font-size:13px}.footer-grid{grid-template-columns:1fr 1fr}.entry-btn{padding:6px 9px}.brand-logo{max-width:min(150px,100%)}.reading-path>a{padding:14px}}
@media(max-width:370px){.brand-logo{max-width:130px}.brand-word{font-size:17px}.entry-btn{font-size:12px;padding:5px 7px}.brand-inner{gap:5px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;transition:none!important;animation:none!important}}