:root{--bg:#F4F7FA;--surface:#fff;--pale:#EAF1F6;--mint:#E9F8F8;--nav:#102E46;--deep:#163C57;--teal:#13B8C5;--blue:#237BD3;--heading:#18364B;--text:#344C60;--muted:#64798A;--line:#DCE6ED;--footer:#0B2539;--max:1200px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.8 Arial,"PingFang SC","Microsoft YaHei",sans-serif;overflow-wrap:break-word}body.drawer-active{overflow:hidden}img{max-width:100%}a{color:#1364A6;text-underline-offset:3px}a:hover{color:#0C8294}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--teal);outline-offset:3px}h1,h2,h3{color:var(--heading);line-height:1.38;margin:0 0 .65em}h1{font-size:clamp(2rem,3vw,2.25rem)}h2{font-size:clamp(1.45rem,2vw,1.75rem)}h3{font-size:1.2rem}p{margin:0 0 1.15em}ul,ol{padding-left:1.5em}li+li{margin-top:.45em}.container{width:min(calc(100% - 56px),var(--max));margin-inline:auto}.skip-link{position:absolute;left:16px;top:-70px;z-index:1000;background:white;padding:10px 18px}.skip-link:focus{top:8px}.site-header{background:var(--nav);color:#fff}.brand-bar{background:#fff}.brand-row{min-height:72px;display:flex;align-items:center;gap:22px}.site-logo{display:inline-flex;align-items:center;min-width:0;flex-shrink:0;color:var(--heading);text-decoration:none}.site-logo img{display:block;max-height:38px;width:auto;height:auto;object-fit:contain}.wordmark{font-size:1.4rem;font-weight:800;line-height:1}.wordmark small{display:block;font-size:.55rem;letter-spacing:.14em;color:#607B8B;margin-top:7px}.brand-tagline{font-size:.85rem;color:var(--muted);margin:0}.brand-tagline span{color:var(--teal);margin:0 5px}.entry-link{margin-left:auto;flex-shrink:0;padding:8px 19px;background:var(--deep);color:#fff;border-radius:9px;text-decoration:none;font-weight:700;font-size:.92rem}.entry-link:hover{background:#23607b;color:#fff}.desktop-nav{background:var(--nav)}.nav-row{display:grid;grid-template-columns:repeat(7,minmax(0,1fr));gap:3px}.nav-row a{position:relative;display:flex;align-items:center;justify-content:center;white-space:nowrap;color:#E4F0F7;text-decoration:none;font-size:.95rem;font-weight:500;min-height:50px}.nav-row a:hover,.nav-row a[aria-current]{color:#fff;background:#1B4963}.nav-row a[aria-current]{font-weight:700}.nav-row a[aria-current]:after{content:"";position:absolute;bottom:0;left:25%;width:50%;height:3px;background:var(--teal)}.menu-trigger{display:none}.mobile-drawer,.drawer-overlay{visibility:hidden;pointer-events:none}.noscript-nav{display:none}.site-footer{background:var(--footer);color:#DCECF5;padding:54px 0 16px;margin-top:64px}.footer-columns{display:grid;grid-template-columns:1.6fr 1fr 1.2fr;gap:46px}.footer-columns p{max-width:460px;color:#C3D7E2;font-size:.93rem}.footer-columns h2{font-size:1rem;color:#fff}.footer-columns a{display:block;color:#DCECF5;text-decoration:none;margin-bottom:9px}.footer-columns a:hover{color:#70DCE3}.footer-brand{font-weight:800;font-size:1.4rem}.footer-brand small{font-weight:400;font-size:.75rem;margin-left:8px;letter-spacing:.08em}.footer-bottom{display:flex;justify-content:space-between;gap:12px;border-top:1px solid #315063;padding-top:20px;font-size:.83rem;color:#C3D7E2}.footer-bottom a{color:#C3D7E2}.mobile-quick{display:none}.back-top{position:fixed;right:22px;bottom:24px;z-index:20;border:0;border-radius:50%;width:44px;height:44px;background:var(--deep);color:white;font-size:22px;box-shadow:0 6px 20px #102E4630;cursor:pointer}.back-top[hidden]{display:none}.section{padding-top:58px}.section:last-child{padding-bottom:32px}.eyebrow{text-transform:uppercase;letter-spacing:.12em;font-size:.78rem;font-weight:800;color:#137B87;margin-bottom:15px}.intro{font-size:1.08rem;max-width:790px;color:#425A69}.breadcrumb{display:flex;gap:12px;align-items:center;font-size:.83rem;color:var(--muted);padding:22px 0 12px}.breadcrumb a{text-decoration:none}.page-head{padding:26px 0 28px;border-bottom:1px solid var(--line)}.page-head .intro{margin:0}.home-hero{display:grid;grid-template-columns:52fr 48fr;align-items:center;gap:44px;padding:58px 0 22px}.home-hero h1{font-size:clamp(2.1rem,3.4vw,2.75rem);letter-spacing:-.02em}.home-hero .intro{font-size:1.05rem}.link-buttons{display:flex;gap:12px;flex-wrap:wrap;margin-top:26px}.button{display:inline-flex;align-items:center;padding:10px 18px;border:1px solid var(--deep);border-radius:9px;text-decoration:none;font-weight:700;background:var(--deep);color:#fff}.button:hover{background:#24607D;color:#fff}.button.secondary{background:#fff;color:var(--deep)}.button.secondary:hover{background:var(--pale)}.media-frame{display:flex;align-items:center;justify-content:center;min-width:0;width:100%;margin:0;padding:10px;background:var(--pale);border-radius:14px;border:1px solid var(--line)}.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--article{--media-limit:220px}.media-frame--banner{--media-limit:210px}.media-frame--mobile{--media-limit:350px;max-width:320px;margin-inline:auto}.media-placeholder{display:flex;align-items:center;justify-content:center;min-height:110px;width:100%;font-size:.84rem;color:#637F8C;text-align:center;background:repeating-linear-gradient(135deg,#EAF1F6,#EAF1F6 12px,#E4EDF3 12px,#E4EDF3 24px);border-radius:8px}.topic-index{display:grid;grid-template-columns:1fr 1fr;column-gap:58px}.topic-item{padding:20px 0;border-top:1px solid #C9D8E2}.topic-item h3{font-size:1.15rem;margin:0 0 6px}.topic-item p{font-size:.94rem;margin-bottom:8px}.topic-item a{font-weight:700}.editor-grid{display:grid;grid-template-columns:2fr 1fr;gap:22px}.editor-lead{background:#fff;padding:28px;border-left:4px solid var(--teal)}.editor-side{display:grid;gap:18px}.editor-side article{background:#EAF1F6;padding:20px}.editor-side h3{font-size:1.13rem}.split-feature{display:grid;grid-template-columns:44fr 56fr;gap:36px;align-items:center}.split-feature.reverse{grid-template-columns:56fr 44fr}.split-feature.reverse .media-frame{order:2}.band{background:var(--mint);padding:34px 0;margin-top:58px}.dark-band{background:var(--deep);color:#E3F1F6;padding:38px;border-radius:14px}.dark-band h2,.dark-band h3{color:#fff}.dark-band a{color:#91E4E8}.triple-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.note-block{background:#fff;border:1px solid var(--line);border-top:3px solid var(--teal);padding:22px;border-radius:0 0 12px 12px}.note-block:nth-child(2){transform:translateY(12px)}.note-block h3{margin-top:0}.reading-steps{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:16px}.reading-step{padding:20px;border-top:3px solid var(--blue);background:#fff}.reading-step .num{font-size:1.5rem;font-weight:800;color:#168A96}.reading-step h3{font-size:1.05rem}.article-body{max-width:800px}.article-body p{line-height:1.83}.prose-section{padding:36px 0;border-bottom:1px solid var(--line)}.prose-section:last-child{border-bottom:0}.prose-section h2{margin-bottom:16px}.prose-section h3{margin-top:24px}.sidebar-layout{display:grid;grid-template-columns:minmax(0,1fr) 265px;gap:45px;align-items:start}.fact-aside{background:var(--pale);padding:22px;border-top:4px solid var(--teal);position:sticky;top:24px}.fact-aside h2{font-size:1.2rem}.fact-aside a{display:block;padding:7px 0}.anchor-nav{display:flex;gap:12px;flex-wrap:wrap;margin:20px 0 4px}.anchor-nav a{padding:7px 14px;border:1px solid #B5CAD8;background:white;border-radius:8px;text-decoration:none;font-size:.9rem;font-weight:700}.table-scroll{overflow-x:auto;max-width:100%;margin:22px 0;border:1px solid var(--line);border-radius:10px;background:white}table{border-collapse:collapse;width:100%;min-width:580px;line-height:1.65;font-size:.94rem}caption{font-weight:700;text-align:left;padding:13px 16px;color:var(--heading)}th,td{text-align:left;padding:13px 16px;border-bottom:1px solid var(--line);vertical-align:top}th{background:var(--pale);color:var(--heading)}tr:last-child td{border-bottom:0}.timeline{counter-reset:step;list-style:none;margin:20px 0;padding:0}.timeline li{counter-increment:step;padding:4px 0 25px 56px;position:relative;border-left:2px solid #BFD7DD;margin-left:17px}.timeline li:last-child{border-left-color:transparent}.timeline li:before{content:counter(step);position:absolute;top:0;left:-18px;width:34px;height:34px;border-radius:50%;background:var(--deep);color:#fff;display:grid;place-items:center;font-weight:800}.timeline strong{display:block;color:var(--heading);margin-bottom:4px}.explain-callout{background:#E9F8F8;border-left:4px solid var(--teal);padding:20px 24px;margin:22px 0}.related{padding:38px 0 14px}.related-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.related-grid a{background:#fff;border:1px solid var(--line);border-radius:10px;text-decoration:none;padding:18px;font-weight:700}.type-matrix{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:15px}.type-matrix article{border:1px solid var(--line);background:white;padding:24px}.type-matrix h3{border-bottom:2px solid var(--teal);padding-bottom:12px}.exhibit-grid{display:grid;grid-template-columns:1fr 1fr;gap:30px}.exhibit-grid article{background:white;padding:18px 18px 25px;border:1px solid var(--line)}.exhibit-grid article:nth-child(2){margin-top:40px}.exhibit-grid article:nth-child(3){grid-column:1/3;display:grid;grid-template-columns:1fr 1fr;gap:28px;align-items:center}.exhibit-grid h3{margin-top:20px}.rule-layout{display:grid;grid-template-columns:225px minmax(0,1fr);gap:40px}.rule-side{position:sticky;top:20px;align-self:start;padding:22px;background:#fff;border:1px solid var(--line)}.rule-side a{display:block;margin:11px 0;text-decoration:none}.rule-side h2{font-size:1.13rem}.faq details{background:white;border:1px solid var(--line);border-radius:9px;padding:0 18px;margin-bottom:10px}.faq summary{font-weight:700;color:var(--heading);cursor:pointer;padding:14px 0}.faq details p{padding:0 0 13px;margin:0}.service-layout{display:grid;grid-template-columns:225px minmax(0,1fr);gap:38px}.service-nav{border-top:4px solid var(--teal);background:#fff;padding:20px;align-self:start}.service-nav a{display:block;margin:9px 0}.policy{border-left:3px solid var(--teal);background:var(--mint);padding:20px 24px}.mini-cards{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.mini-cards article{background:white;padding:24px;border:1px solid var(--line)}.source-note{font-size:.91rem;color:var(--muted)}
@media(max-width:1100px){.container{width:min(calc(100% - 44px),var(--max))}.nav-row a{font-size:.87rem}.home-hero{gap:25px}}
@media(max-width:920px){.brand-row{min-height:62px;display:grid;grid-template-columns:42px minmax(0,1fr) auto;gap:12px}.menu-trigger{display:flex;flex-direction:column;justify-content:center;gap:5px;align-items:center;width:40px;height:40px;border:1px solid var(--line);border-radius:8px;background:white;cursor:pointer}.menu-trigger span{height:2px;width:18px;background:var(--heading)}.site-logo{justify-content:center;justify-self:center}.site-logo img{max-height:30px}.brand-tagline,.desktop-nav{display:none}.entry-link{margin:0;font-size:.78rem;padding:8px 11px;min-height:39px;display:flex;align-items:center;justify-content:center}.drawer-overlay{position:fixed;inset:0;background:#071A2F90;z-index:90;opacity:0;transition:opacity .2s;visibility:hidden;pointer-events:none}.drawer-overlay.is-open{opacity:1;visibility:visible;pointer-events:auto}.mobile-drawer{display:block;position:fixed;inset:0 auto 0 0;width:min(86vw,340px);max-width:100%;background:white;z-index:91;overflow-y:auto;transform:translateX(-105%);transition:transform .23s;visibility:hidden;pointer-events:none;box-shadow:8px 0 30px #0002}.mobile-drawer.is-open{transform:translateX(0);visibility:visible;pointer-events:auto}.drawer-top{display:flex;align-items:center;justify-content:space-between;padding:14px 20px;border-bottom:1px solid var(--line)}.drawer-close{width:38px;height:38px;border:1px solid var(--line);background:white;font-size:28px;cursor:pointer}.mobile-drawer nav{padding:12px 20px 40px}.mobile-drawer nav p{margin:20px 0 8px;color:var(--muted);font-weight:800;font-size:.82rem}.mobile-drawer nav a{display:block;padding:10px 8px;text-decoration:none;border-bottom:1px solid var(--line);color:var(--heading)}.noscript-nav{display:flex;flex-wrap:wrap;gap:8px;padding:12px 22px;background:#EAF1F6}.noscript-nav a{padding:4px 9px}.mobile-quick{display:flex;flex-wrap:wrap;justify-content:space-around;padding-top:32px;gap:12px}.mobile-quick a{font-size:.9rem}.home-hero{padding-top:40px}.section{padding-top:46px}}
@media(max-width:760px){.home-hero,.split-feature,.split-feature.reverse,.editor-grid,.sidebar-layout,.rule-layout,.service-layout,.exhibit-grid,.mini-cards{grid-template-columns:1fr}.home-hero .media-frame{margin-top:10px}.split-feature.reverse .media-frame{order:0}.fact-aside,.rule-side{position:static}.exhibit-grid article:nth-child(2){margin-top:0}.exhibit-grid article:nth-child(3){grid-column:auto;display:block}.triple-grid,.type-matrix{grid-template-columns:1fr 1fr}.reading-steps{grid-template-columns:1fr 1fr}.footer-columns{grid-template-columns:1fr 1fr;gap:26px}.related-grid{grid-template-columns:1fr}.band{margin-top:40px}}
@media(max-width:640px){.container{width:calc(100% - 32px)}body{font-size:15px}h1{font-size:clamp(1.56rem,6vw,1.82rem)}h2{font-size:1.32rem}h3{font-size:1.09rem}.home-hero h1{font-size:clamp(1.75rem,7.2vw,2rem)}.home-hero{padding-top:29px}.section{padding-top:35px}.page-head{padding:17px 0}.topic-index,.triple-grid,.type-matrix,.reading-steps,.footer-columns{grid-template-columns:1fr}.topic-index{gap:0}.note-block:nth-child(2){transform:none}.media-frame{padding:8px}.media-frame--hero{--media-limit:205px}.media-frame--feature{--media-limit:185px}.media-frame--card{--media-limit:145px}.media-frame--article{--media-limit:175px}.media-frame--banner{--media-limit:135px}.media-frame--mobile{--media-limit:285px;max-width:250px}.footer-bottom{display:block}.site-footer{margin-top:38px;padding-top:36px}.exhibit-grid{gap:20px}.exhibit-grid article{padding:16px}.link-buttons .button{font-size:.92rem}.prose-section{padding:27px 0}.dark-band{padding:24px}.mini-cards article{padding:18px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation:none!important;transition:none!important}}