:root{--color-primary:#123B5D;--color-primary-2:#1E5B89;--color-secondary:#2D8C8A;--color-accent:#7EC7C4;--color-bg:#F7FAFC;--color-surface:#FFF;--color-surface-muted:#EEF4F7;--color-border:#D9E3EA;--color-text:#163047;--color-text-muted:#4E6678;--color-text-light:#6F8797;--color-success:#3A8F63;--color-warning:#D28A2E;--color-info:#4B8FD8;--radius-sm:8px;--radius-md:14px;--radius-lg:20px;--shadow-sm:0 2px 8px rgba(18,59,93,.06);--shadow-md:0 8px 24px rgba(18,59,93,.08);--max-content-width:1180px;--max-text-width:760px}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;color:var(--color-text);background:var(--color-bg);font:17px/1.7 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}a{color:var(--color-primary-2);text-underline-offset:4px}a:hover{color:#166a68}button,input{font:inherit}a,button,summary{touch-action:manipulation}:focus-visible{outline:3px solid #197c9d;outline-offset:5px}h1,h2,h3{color:var(--color-primary);line-height:1.18;letter-spacing:-.03em}h1{font-size:clamp(2.3rem,4.1vw,3.5rem);margin:16px 0 22px}h2{font-size:clamp(1.65rem,2.8vw,2.3rem);margin:0 0 22px}h3{font-size:1.22rem;margin:0 0 12px}p{margin:0 0 20px}small{font-size:13px}img{max-width:100%;height:auto;display:block}.wrap{max-width:var(--max-content-width);margin:auto;width:calc(100% - 64px)}header{background:white;border-bottom:1px solid var(--color-border)}.masthead{display:flex;justify-content:space-between;align-items:center;min-height:104px;gap:24px}.brand{display:flex;align-items:center;gap:13px;text-decoration:none;color:var(--color-primary);font-size:24px;font-weight:750;letter-spacing:-.7px;line-height:1.25}.brand small{display:block;color:var(--color-text-muted);font-size:12px;font-weight:450;letter-spacing:.25px;margin-top:7px}.brand-mark{display:flex;align-items:center;justify-content:center;background:var(--color-primary);color:white;width:52px;height:52px;border-radius:12px;font-size:21px;letter-spacing:-1px;position:relative}.brand-mark span{position:absolute;right:-4px;top:-10px;color:var(--color-secondary);font-size:30px}.mast-note{font-size:13px;color:var(--color-text-muted);line-height:1.6}.nav-inner{display:flex;gap:32px;align-items:center;min-height:56px;border-top:1px solid var(--color-border)}.nav-inner a{font-size:14px;text-decoration:none;font-weight:650;padding:16px 0}.nav-inner a[aria-current]{box-shadow:inset 0 -3px var(--color-secondary)}.nav-about{margin-left:auto;color:var(--color-text-muted)}.menu-toggle{display:none}.skip{position:fixed;top:-100px;left:20px;background:white;padding:10px;z-index:10}.skip:focus{top:10px}.eyebrow,.section-label{font-size:12px;letter-spacing:2px;font-weight:750;color:#246f72}.hero{padding:65px 0 48px;background:linear-gradient(115deg,#eef6f8 0%,#f7fafc 65%);border-bottom:1px solid var(--color-border)}.hero-grid{display:grid;grid-template-columns:1.04fr 1fr;gap:48px;align-items:center}.hero p{font-size:18px;max-width:590px;color:var(--color-text-muted)}.hero h1 em{font-style:normal;color:var(--color-secondary)}.hero-art{border:1px solid var(--color-border);background:white;border-radius:var(--radius-lg);padding:24px 18px 16px;box-shadow:var(--shadow-md)}.hero-art img{margin:15px 0}.hero-art .art-label{font-size:11px;letter-spacing:1.7px;font-weight:700;color:var(--color-text-muted)}.art-footer{display:flex;gap:8px;font-size:11px;border-top:1px solid var(--color-border);padding-top:15px;justify-content:space-between;color:var(--color-text-muted)}.buttons{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}.button{display:inline-flex;align-items:center;justify-content:center;gap:16px;text-decoration:none;background:var(--color-primary);color:white;padding:12px 19px;border-radius:6px;font-size:14px;font-weight:650;border:1px solid var(--color-primary)}.button:hover{background:var(--color-primary-2);color:white}.button.secondary{color:var(--color-primary);background:white;border-color:#b8cad5}.button.light{background:white;color:var(--color-primary);border-color:white;flex-shrink:0}.hero-note{font-size:12px!important;margin:22px 0 0!important}.intro-strip{display:grid;grid-template-columns:1fr 2.2fr;gap:60px;padding:32px 0;border-bottom:1px solid var(--color-border);align-items:center}.intro-strip h2{font-size:20px;margin:0}.intro-strip p{font-size:15px;margin:0;color:var(--color-text-muted)}.section{padding:64px 0}.section-label{margin-bottom:12px}.section-head{display:flex;align-items:end;justify-content:space-between;gap:30px;margin-bottom:28px}.section-head h2{margin:0}.section-head p{max-width:425px;font-size:15px;margin:0;color:var(--color-text-muted)}.topic-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}.topic-card{display:flex;flex-direction:column;background:white;padding:26px;border:1px solid var(--color-border);border-radius:12px;text-decoration:none;transition:border-color .15s,transform .15s}.topic-card:hover,.guide-card:hover{border-color:var(--color-secondary);transform:translateY(-2px)}.topic-card .num{font-size:12px;color:var(--color-secondary);font-weight:650;margin-bottom:25px;letter-spacing:1px}.topic-card p{font-size:14px;color:var(--color-text-muted)}.text-link{font-size:13px;font-weight:700;color:var(--color-primary-2);margin-top:auto}.text-link span{float:right}.band{background:var(--color-surface-muted);border-block:1px solid var(--color-border)}.process{display:grid;grid-template-columns:repeat(3,1fr);gap:40px}.process div{border-top:2px solid var(--color-accent);padding-top:22px}.process b{font-size:12px;color:var(--color-secondary);display:block;margin-bottom:15px}.process p{font-size:15px;color:var(--color-text-muted);margin:0}.split{display:grid;grid-template-columns:.8fr 1.2fr;align-items:center;gap:56px}.split.reverse{grid-template-columns:1.2fr .8fr}.split p{color:var(--color-text-muted);font-size:16px}.split figure{margin:0}.mini-links{display:flex;flex-wrap:wrap;gap:10px 20px;font-size:14px;font-weight:600;margin:20px 0}.guide-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.guide-card{background:white;border:1px solid var(--color-border);border-radius:12px;padding:26px;text-decoration:none;display:flex;flex-direction:column}.guide-card p{font-size:14px;color:var(--color-text-muted)}.guide-card h3{font-size:19px}.cta{background:var(--color-primary);padding:38px 40px;border-radius:14px;display:flex;align-items:center;justify-content:space-between;gap:25px;margin:40px 0 65px}.cta h2{color:white;font-size:25px;margin:0 0 10px}.cta p{color:#d1e2eb;font-size:15px;margin:0}figure{margin:30px 0;border:1px solid var(--color-border);border-radius:14px;overflow:hidden;background:white}figure img{width:100%}figcaption{border-top:1px solid var(--color-border);padding:14px 18px;font-size:12px;line-height:1.65;color:var(--color-text-muted)}figcaption a{white-space:nowrap}.table-scroll{overflow-x:auto;margin:25px 0 30px;border:1px solid var(--color-border);border-radius:10px}table{border-collapse:collapse;width:100%;font-size:14px;background:white;min-width:530px}th,td{text-align:left;padding:16px 20px;border-bottom:1px solid var(--color-border);vertical-align:top}thead th{background:var(--color-primary);color:white;font-weight:600}tbody tr:nth-child(even){background:var(--color-bg)}tbody th{font-weight:650;min-width:140px}.questions{border-top:1px solid var(--color-border)}details{border-bottom:1px solid var(--color-border)}summary{display:flex;gap:24px;align-items:center;justify-content:space-between;cursor:pointer;padding:21px 0;list-style:none}summary::-webkit-details-marker{display:none}summary h3{font-size:17px;line-height:1.45;letter-spacing:0;margin:0}summary span{font-size:24px;color:var(--color-secondary)}details[open] summary span{transform:rotate(45deg)}details p{font-size:16px;color:var(--color-text-muted);max-width:740px;padding-right:20px}.breadcrumbs{padding-top:24px;padding-bottom:20px;font-size:12px;color:var(--color-text-muted)}.breadcrumbs ol{list-style:none;padding:0;margin:0;display:flex;flex-wrap:wrap;gap:9px}.breadcrumbs li+li:before{content:'›';padding-right:9px}.breadcrumbs a{text-decoration:none}.article-head{padding:24px 0 35px;max-width:850px}.article-head h1{font-size:clamp(2.1rem,4vw,3.3rem)}.article-head .lead{font-size:20px;color:var(--color-text-muted)}.meta{font-size:12px;color:var(--color-text-muted);display:flex;flex-wrap:wrap;gap:16px}.article-layout{display:grid;grid-template-columns:minmax(0,790px) 260px;gap:65px;align-items:start;padding-bottom:30px}.article-body{min-width:0}.article-body>section{margin:45px 0}.article-body section h2{font-size:28px}.article-body p,.article-body li{font-size:17px}.article-body ul,.article-body ol{padding-left:23px}.article-body li{margin-bottom:10px}.article-body .guide-grid{grid-template-columns:1fr 1fr}.article-body .guide-card h3{font-size:17px}.article-body .guide-card p{font-size:14px}.toc{position:sticky;top:25px;padding:22px;border:1px solid var(--color-border);border-radius:12px;background:white;font-size:13px}.toc strong{font-size:12px;letter-spacing:1px}.toc a{display:block;text-decoration:none;padding:10px 0;border-bottom:1px solid var(--color-border);line-height:1.5}.toc p{font-size:12px;margin:20px 0 0;color:var(--color-text-muted)}.callout{background:#e9f4f2;border-left:3px solid var(--color-secondary);padding:22px 25px;border-radius:0 10px 10px 0;margin:25px 0}.callout strong{font-size:12px;letter-spacing:1.4px;text-transform:uppercase}.callout p{font-size:16px;margin:8px 0 0}.callout.warning{background:#fff5e5;border-color:var(--color-warning)}.callout.limitation{background:var(--color-surface-muted);border-color:#7b98aa}.sources{background:var(--color-surface-muted);padding:25px;border-radius:12px}.sources h2{font-size:20px!important}.sources li{font-size:13px!important}.sources p{font-size:13px!important}.plain{max-width:760px;padding-bottom:55px}.plain h1{font-size:42px}.plain h2{font-size:26px;margin-top:35px}footer{background:#eaf1f5;border-top:1px solid var(--color-border);padding:50px 0 25px}.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr;gap:50px}.footer-grid p{font-size:14px;color:var(--color-text-muted);margin-top:20px}.footer-grid h2{font-size:13px;letter-spacing:0;margin:0 0 18px}.footer-grid>div>a:not(.brand){display:block;font-size:13px;margin:7px 0;text-decoration:none;color:var(--color-text-muted)}.footer-bottom{display:flex;justify-content:space-between;gap:40px;border-top:1px solid #cbd9e2;margin-top:40px;padding-top:23px;font-size:11px;color:var(--color-text-muted)}.footer-bottom p{max-width:740px;margin:0}.footer-bottom span{white-space:nowrap}@media(max-width:1050px){.nav-inner{gap:20px}.nav-about{display:none}.hero-grid{gap:25px}.hero h1{font-size:42px}.topic-grid{grid-template-columns:repeat(2,1fr)}.article-layout{gap:30px;grid-template-columns:minmax(0,1fr) 220px}.split{gap:30px}.brand{font-size:22px}}@media(max-width:760px){.wrap{width:calc(100% - 36px)}.masthead{min-height:86px}.mast-note{display:none}.brand{font-size:20px}.brand small{font-size:10px}.brand-mark{width:43px;height:43px;font-size:18px}.menu-toggle{display:block;background:white;border:1px solid var(--color-border);padding:7px 10px;border-radius:6px;font-size:13px;color:var(--color-primary)}.nav-inner{flex-wrap:wrap;gap:0;padding:8px 0}.nav-inner a{width:50%;padding:9px 12px}.js #primary-nav{display:none}.js #primary-nav.open{display:block}.hero{padding:35px 0}.hero-grid,.split,.split.reverse{grid-template-columns:1fr}.hero h1{font-size:38px}.hero p{font-size:16px}.hero-art{padding:18px;max-width:570px}.hero-note{font-size:11px!important}.intro-strip{grid-template-columns:1fr;gap:13px;padding:25px 0}.section{padding:40px 0}.section-head{display:block}.section-head p{margin-top:15px}.topic-card{padding:22px}.topic-card h3{font-size:18px}.process{grid-template-columns:1fr;gap:24px}.guide-grid{grid-template-columns:1fr}.split.reverse>figure{order:2}.article-layout{display:block}.toc{position:static;margin:0 0 35px}.article-head{padding-top:8px}.article-head .lead{font-size:18px}.article-head h1{font-size:36px}.article-body>section{margin:35px 0}.article-body .guide-grid{grid-template-columns:1fr}.cta{display:block;padding:28px;margin-bottom:40px}.cta .button{margin-top:22px}.footer-grid{grid-template-columns:1fr 1fr;gap:30px}.footer-grid>div:first-child{grid-column:1/-1}.footer-bottom{display:block}.footer-bottom span{display:block;margin-top:20px}.plain h1{font-size:34px}.art-footer{font-size:10px}}@media(max-width:380px){.topic-grid{grid-template-columns:1fr}.hero h1{font-size:33px}.brand{font-size:17px}.brand small{font-size:9px}.buttons .button{width:100%}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}@media print{header,footer,.toc,.cta,.menu-toggle{display:none}body{background:white}.wrap{width:100%}.article-layout{display:block}details>p{display:block}a{color:inherit}.article-head h1{font-size:30px}}

/* Cluster expansion: retain existing tokens and article design. */
.topic-grid{grid-template-columns:repeat(3,minmax(0,1fr))}.nav-inner{gap:22px}.nav-inner a{white-space:nowrap}.cluster-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.cluster-card{padding:20px;background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius-sm)}.cluster-card h3{font-size:18px;margin-bottom:12px}.cluster-card ul{padding-left:18px;margin:0}.cluster-card li{font-size:15px;margin:8px 0}.cluster-card a{text-decoration-thickness:1px}.article-body>section>p{max-width:var(--max-text-width)}
@media(max-width:1050px){.topic-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.nav-inner{gap:16px}.nav-inner a{font-size:13px}}
@media(max-width:960px){.mast-note{display:none}.menu-toggle{display:block;background:white;border:1px solid var(--color-border);padding:7px 10px;border-radius:6px;font-size:13px;color:var(--color-primary)}.nav-inner{flex-wrap:wrap;gap:0;padding:8px 0}.nav-inner a{width:50%;padding:9px 12px;white-space:normal}.js #primary-nav{display:none}.js #primary-nav.open{display:block}}
@media(max-width:560px){.topic-grid,.cluster-grid{grid-template-columns:1fr}.nav-inner a{font-size:14px}.cluster-card{padding:18px}}