@font-face{font-family:'Signal Inter';src:url('inter-regular.woff2') format('woff2');font-weight:400;font-display:swap}
@font-face{font-family:'Signal Inter';src:url('inter-medium.woff2') format('woff2');font-weight:500;font-display:swap}
@font-face{font-family:'Signal Inter';src:url('inter-semibold.woff2') format('woff2');font-weight:600 900;font-display:swap}
@font-face{font-family:'Signal Mono';src:url('mono.woff2') format('woff2');font-weight:400 700;font-display:swap}
:root{
  --signal-ink:#18212e;--signal-muted:#596779;--signal-blue:#245ad5;--signal-blue-hover:#1947b4;
  --signal-teal:#216d65;--signal-violet:#6951a6;--signal-paper:#fff;--signal-wash:#f6f8fb;
  --signal-navy:#101d30;--signal-line:#dfe5ee;--signal-radius:16px;--signal-control-radius:8px;
  --signal-sans:'Signal Inter',Inter,ui-sans-serif,system-ui,sans-serif;
  --signal-mono:'Signal Mono',ui-monospace,monospace;
  --signal-width:1320px;--signal-gutter:24px;
}
@media(min-width:768px){:root{--signal-gutter:40px}}
@media(min-width:1200px){:root{--signal-gutter:64px}}

*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:112px}
body{margin:0;background:var(--signal-paper);color:var(--signal-ink);font-family:var(--signal-sans);font-size:16px;line-height:1.65;-webkit-font-smoothing:antialiased}
button,input,select{font:inherit}
button,a{-webkit-tap-highlight-color:transparent}
a{color:var(--signal-blue);text-underline-offset:4px}
a:hover{color:var(--signal-blue-hover)}
button{cursor:pointer}
button:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid #8fb0ff;outline-offset:5px}
h1,h2,h3,h4,p{margin:0}
h1,h2,h3,h4{font-weight:600;line-height:1.15;letter-spacing:-.04em;text-wrap:balance}
h1{font-size:clamp(40px,4.5vw,68px);line-height:1.04;letter-spacing:-.055em}
h2{font-size:clamp(32px,3.1vw,44px)}
h3{font-size:24px}
p{color:var(--signal-muted)}
strong{font-weight:600;color:var(--signal-ink)}
.wrap{max-width:calc(var(--signal-width) + var(--signal-gutter)*2);margin-inline:auto;padding-inline:var(--signal-gutter)}
.skip-link{position:fixed;top:-100px;left:24px;padding:12px 20px;z-index:100;background:white}
.skip-link:focus{top:12px}
.site-nav{position:sticky;top:0;background:rgba(255,255,255,.97);border-bottom:1px solid var(--signal-line);z-index:30}
.nav-inner{height:84px;display:flex;align-items:center;justify-content:space-between;gap:24px}
.brand{display:flex;align-items:center;flex-shrink:0}
.brand img{width:156px;height:auto;display:block}
.nav-links{display:flex;align-items:center;gap:30px}
.nav-links a{text-decoration:none;font-size:14px;font-weight:500;color:var(--signal-muted)}
.nav-links a[aria-current]{color:var(--signal-blue)}
.nav-links .button{font-size:14px;color:white}
.button{display:inline-flex;align-items:center;justify-content:center;gap:24px;padding:13px 20px;min-height:48px;border:1px solid var(--signal-blue);border-radius:var(--signal-control-radius);background:var(--signal-blue);color:#fff;font-size:15px;font-weight:500;line-height:1.35;text-decoration:none;transition:background .18s,border-color .18s}
.button:hover{background:var(--signal-blue-hover);border-color:var(--signal-blue-hover);color:white}
.button.secondary{background:white;color:var(--signal-ink);border-color:var(--signal-line)}
.button.secondary:hover{background:var(--signal-wash);color:var(--signal-blue)}
.nav-toggle{display:none;border:1px solid var(--signal-line);border-radius:8px;background:white;padding:8px 12px;min-height:44px;font-size:14px}
.eyebrow{display:block;font-family:var(--signal-mono);font-size:12px;font-weight:400;letter-spacing:.1em;line-height:1.5;text-transform:uppercase;color:var(--signal-blue)}
.method-hero{padding-block:88px 64px}
.hero-grid{display:grid;grid-template-columns:1.1fr 1fr;align-items:center;gap:88px}
.hero-copy .eyebrow{margin-bottom:26px}
.hero-copy h1 span{color:var(--signal-blue)}
.hero-copy>p{font-size:19px;line-height:1.65;max-width:520px;margin-top:28px}
.hero-actions{display:flex;flex-wrap:wrap;align-items:center;gap:24px;margin-top:32px}
.hero-actions .text-link{font-size:15px;text-decoration:none;font-weight:500}
.hero-meta{display:flex;flex-wrap:wrap;gap:8px 20px;color:var(--signal-muted);font-size:12px;margin-top:32px}
.hero-meta span+span:before{content:'·';margin-right:20px;color:#99a4b3}
.method-map{position:relative;background:linear-gradient(135deg,#f6f8ff,#f4f9f8);border:1px solid #e2e8f1;border-radius:20px;padding:28px}
.map-label{display:flex;align-items:center;justify-content:space-between;color:var(--signal-muted);font-family:var(--signal-mono);font-size:11px;letter-spacing:.07em;text-transform:uppercase;margin-bottom:28px}
.map-label b{font-weight:400;color:var(--signal-teal);display:flex;align-items:center;gap:6px}
.map-label b:before{content:'';width:5px;height:5px;border-radius:50%;background:currentColor}
.map-stage{display:grid;grid-template-columns:30px 1fr auto;gap:14px;align-items:center;padding:20px;background:white;border:1px solid var(--signal-line);border-radius:10px}
.map-stage>span{font-family:var(--signal-mono);font-size:12px;color:var(--signal-blue)}
.map-stage strong{display:block;font-size:15px;line-height:1.4}
.map-stage p{font-size:12px;margin-top:4px}
.stage-icon{color:var(--signal-blue);font-size:22px}
.map-connector{height:28px;margin-left:35px;border-left:1px solid #bccde9;position:relative}
.map-connector:after{content:'';position:absolute;bottom:0;left:-3px;width:5px;height:5px;border-bottom:1px solid #9fb6d9;border-right:1px solid #9fb6d9;transform:rotate(45deg)}
.map-results{display:grid;grid-template-columns:repeat(3,1fr);gap:8px}
.map-result{border-radius:10px;padding:18px 12px;text-decoration:none;border:1px solid #cfdbf6;background:#eef3ff;transition:transform .18s}
.map-result:hover{transform:translateY(-3px)}
.map-result:nth-child(2){background:#eaf5f2;border-color:#c9e4dc}
.map-result:nth-child(3){background:#f3effa;border-color:#e0d4ee}
.map-result b{display:block;font-family:var(--signal-mono);font-weight:400;font-size:28px;color:var(--signal-blue);line-height:1.2}
.map-result:nth-child(2) b{color:var(--signal-teal)}
.map-result:nth-child(3) b{color:var(--signal-violet)}
.map-result span{display:block;font-size:11px;color:var(--signal-ink);line-height:1.4;margin-top:10px}
.map-caption{font-size:11px;margin-top:20px;text-align:center;color:var(--signal-muted)}
.scope-note{display:flex;gap:24px;padding-block:28px;border-block:1px solid var(--signal-line)}
.scope-note .eyebrow{min-width:160px;flex-shrink:0;padding-top:3px;color:var(--signal-muted)}
.scope-note p{font-size:14px;max-width:950px}
.guide-layout{display:grid;grid-template-columns:180px minmax(0,1fr);gap:72px;align-items:start;padding-top:72px}
.guide-nav{position:sticky;top:116px;padding-bottom:30px}
.guide-nav .eyebrow{font-size:11px;color:#778394;margin:0 0 16px 12px}
.guide-nav ol{list-style:none;margin:0;padding:0}
.guide-nav li{margin:4px 0}
.guide-nav a{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--signal-muted);font-size:13px;padding:10px 12px;border-radius:7px;line-height:1.4}
.guide-nav a span{font-family:var(--signal-mono);font-size:10px;color:#8b97a6}
.guide-nav a:hover{background:var(--signal-wash)}
.guide-nav a[aria-current]{background:#edf2fe;color:var(--signal-blue)}
.guide-nav a[aria-current] span{color:var(--signal-blue)}
.guide-nav .guide-download{margin-top:28px;border-top:1px solid var(--signal-line);border-radius:0;padding-top:22px;color:var(--signal-blue)}
.guide-mobile{display:none}
.guide-body{min-width:0}
.chapter{padding-bottom:80px;margin-bottom:72px;border-bottom:1px solid var(--signal-line);scroll-margin-top:112px}
.chapter .eyebrow{margin-bottom:18px}
.chapter-lead{font-size:17px;line-height:1.75;margin-top:24px;max-width:800px}
.chapter-intro{max-width:810px}
.score-cards{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin:36px 0 24px}
.score-card{padding:24px;border-radius:12px;background:#f1f5ff;border:1px solid #dce5fa}
.score-card:nth-child(2){background:#edf7f3;border-color:#d9e9e2}
.score-card:nth-child(3){background:#f5f1fa;border-color:#e5ddef}
.score-card .score-symbol{font-family:var(--signal-mono);font-size:28px;color:var(--signal-blue);margin-bottom:20px}
.score-card:nth-child(2) .score-symbol{color:var(--signal-teal)}
.score-card:nth-child(3) .score-symbol{color:var(--signal-violet)}
.score-card h3{font-size:18px;letter-spacing:-.025em}
.score-card p{font-size:14px;line-height:1.65;margin-top:12px}
.small-note{font-size:13px;line-height:1.7;color:var(--signal-muted)}
.subheading{font-size:25px;margin:48px 0 16px}
.dimension-list{margin-top:24px}
.dimension-row{display:grid;grid-template-columns:180px 1fr;gap:32px;border-top:1px solid var(--signal-line);padding:25px 0}
.dimension-row h3{font-size:18px;letter-spacing:-.02em;padding-top:2px}
.dimension-row h3 span{display:block;font-family:var(--signal-mono);font-size:11px;font-weight:400;letter-spacing:0;color:var(--signal-muted);margin-top:9px}
.dimension-row p{font-size:15px}
.dimension-row p+p{margin-top:12px}
.sources-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin-top:36px}
.source-card{border:1px solid var(--signal-line);border-radius:12px;padding:24px;display:flex;flex-direction:column}
.source-heading{display:flex;gap:12px;justify-content:space-between;align-items:center;margin-bottom:20px}
.source-heading>span:first-child{font-family:var(--signal-mono);font-size:10px;text-transform:uppercase;letter-spacing:.03em;color:var(--signal-muted)}
.status{font-size:10px;line-height:1.4;padding:4px 8px;border-radius:4px;background:#eaf5f0;color:var(--signal-teal);white-space:nowrap}
.status.roadmap{background:#f5f0e4;color:#89651b}
.source-card h3{font-size:19px;letter-spacing:-.025em;line-height:1.35;text-wrap:pretty}
.source-card>p{font-size:14px;line-height:1.7;margin-top:14px;flex:1}
.source-tags{display:flex;flex-wrap:wrap;gap:6px 14px;padding-top:18px;margin-top:22px;border-top:1px solid #edf0f5}
.source-tags span{font-size:11px;color:var(--signal-muted)}
.detail-note{border-left:2px solid #b7c9ec;padding:4px 0 4px 20px;font-size:13px;margin-top:28px;color:var(--signal-muted)}
.formula-explorer{margin-top:36px;background:var(--signal-navy);border-radius:16px;color:white;overflow:hidden}
.formula-tabs{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));padding:8px;background:#17263b;gap:6px}
.formula-tab{border:0;background:transparent;color:#acb9cf;font-size:12px;padding:13px 8px;border-radius:7px;line-height:1.5}
.formula-tab[aria-selected=true]{background:#314763;color:white}
.formula-panel{padding:32px;min-height:230px}
.formula-panel[hidden]{display:none}
.formula-panel .eyebrow{color:#a4bcf9;margin-bottom:22px;font-size:10px}
.formula-panel code{display:block;font-family:var(--signal-mono);font-size:clamp(15px,1.6vw,21px);color:white;line-height:1.8;overflow-wrap:anywhere}
.formula-panel code span{color:#94c9ba}
.formula-panel p{font-size:14px;color:#bdc9db;max-width:660px;margin-top:24px}
.bands{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;margin-top:28px}
.band{padding:18px 16px;border-top:3px solid var(--band-color);background:var(--signal-wash);border-radius:0 0 8px 8px}
.band b{display:block;font-size:22px;font-weight:500;letter-spacing:-.04em}
.band span{display:block;font-size:12px;color:var(--signal-muted);margin-top:4px}
.band small{display:block;font-size:11px;color:var(--signal-muted);line-height:1.5;margin-top:10px}
.models{margin-top:32px;border-top:1px solid var(--signal-line)}
.model{border-bottom:1px solid var(--signal-line)}
.model summary{display:grid;grid-template-columns:32px 1fr 24px;align-items:center;gap:12px;padding:24px 0;cursor:pointer;list-style:none}
.model summary::-webkit-details-marker{display:none}
.model summary>span{font-family:var(--signal-mono);font-size:11px;color:#8190a5}
.model summary h3{font-size:18px;letter-spacing:-.02em;line-height:1.4;text-wrap:pretty}
.model summary small{display:block;font-family:var(--signal-mono);font-size:10px;color:var(--signal-blue);margin-bottom:5px;letter-spacing:.03em;font-weight:400}
.model summary:after{content:'+';font-size:22px;font-weight:400;color:var(--signal-blue)}
.model[open] summary:after{content:'−'}
.model-body{padding:0 36px 28px 44px}
.model-body p{font-size:15px;line-height:1.75}
.model-body code{display:block;margin-top:20px;padding:16px 20px;border-radius:8px;background:var(--signal-wash);font-family:var(--signal-mono);font-size:12px;color:#31507c;overflow-wrap:anywhere}
.validation-stats{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:24px;margin-top:36px;padding-block:28px;border-block:1px solid var(--signal-line)}
.validation-stat b{display:block;font-size:42px;line-height:1.2;font-weight:500;letter-spacing:-.055em}
.validation-stat p{margin-top:12px;font-size:12px;line-height:1.6}
.research-line{display:flex;align-items:center;gap:16px;margin-top:24px;font-size:12px;color:var(--signal-muted)}
.research-line:before{content:'';width:7px;height:7px;border-radius:50%;background:var(--signal-teal)}
.friction-visual{display:grid;grid-template-columns:.8fr 1.5fr;gap:40px;align-items:center;background:var(--signal-wash);border:1px solid var(--signal-line);border-radius:16px;padding:32px;margin:32px 0 24px}
.friction-total b{display:block;font-size:62px;line-height:1.05;letter-spacing:-.06em;font-weight:500;color:var(--signal-blue)}
.friction-total p{font-size:13px;margin-top:16px}
.bar-row+.bar-row{margin-top:20px}
.bar-caption{display:flex;justify-content:space-between;gap:12px;font-size:12px;color:var(--signal-muted);margin-bottom:9px}
.bar-caption b{color:var(--signal-ink);font-weight:500}
.bar-track{height:8px;border-radius:3px;background:#e4e9f1;overflow:hidden}
.bar-fill{height:100%;border-radius:3px;background:var(--bar-color)}
.friction-note{font-size:14px;line-height:1.8;margin-top:24px}
.limits-grid{display:grid;grid-template-columns:1fr 1fr;gap:28px;margin-top:32px}
.limit-card{border-top:2px solid #c2cfe2;padding-top:24px}
.limit-card h3{font-size:20px;line-height:1.4;text-wrap:pretty}
.limit-card p{margin-top:14px;font-size:15px;line-height:1.8}
.request-panel{background:linear-gradient(130deg,#f2f5fd,#f6f9f8);border:1px solid var(--signal-line);border-radius:16px;padding:40px;margin-bottom:88px}
.request-panel .eyebrow{margin-bottom:20px}
.request-panel h2{max-width:560px}
.request-panel>p{font-size:16px;line-height:1.8;max-width:710px;margin-top:24px}
.request-panel .hero-actions{margin-top:28px}
.site-footer{border-top:1px solid var(--signal-line);background:var(--signal-wash);padding-block:48px 24px}
.footer-grid{display:grid;grid-template-columns:1.6fr 1fr 1fr 1.2fr;gap:40px}
.footer-lede{font-size:14px;max-width:340px}
.footer-heading{font-family:var(--signal-mono);text-transform:uppercase;letter-spacing:.05em;font-size:10px;color:var(--signal-muted);margin-bottom:16px}
.footer-links{display:flex;flex-direction:column;align-items:start;gap:9px}
.footer-links a,.footer-links span{font-size:12px;color:var(--signal-muted);text-decoration:none}
.footer-links a:hover{color:var(--signal-blue);text-decoration:underline}
.footer-bottom{display:flex;justify-content:space-between;gap:24px;border-top:1px solid var(--signal-line);padding-top:20px;margin-top:40px;color:var(--signal-muted);font-size:11px}
@media(min-width:1600px){.method-hero{padding-block:100px 72px}}
@media(max-width:1100px){.hero-grid{gap:40px}.guide-layout{gap:36px;grid-template-columns:160px minmax(0,1fr)}.nav-links{gap:20px}.score-card{padding:18px}.dimension-row{grid-template-columns:150px 1fr;gap:24px}.source-card{padding:20px}.source-heading{align-items:start}.friction-visual{gap:24px;padding:24px}.friction-total b{font-size:50px}}
@media(max-width:900px){.hero-grid{grid-template-columns:1fr 1fr;gap:32px}.method-map{padding:20px}.map-stage{padding:16px;gap:8px;grid-template-columns:22px 1fr}.stage-icon{display:none}.map-results{gap:6px}.map-result{padding:16px 8px}.guide-layout{display:block;padding-top:48px}.guide-nav{display:none}.guide-mobile{display:block;position:sticky;top:84px;z-index:20;background:white;border-bottom:1px solid var(--signal-line);padding-block:10px}.guide-mobile select{border:0;background:var(--signal-wash);padding:12px;color:var(--signal-ink);width:100%;font-size:14px;border-radius:8px}.guide-mobile label{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}html{scroll-padding-top:160px}.chapter{scroll-margin-top:160px}.nav-links{gap:16px}.nav-links>a:not(.button){font-size:12px}.footer-grid{grid-template-columns:1fr 1fr}}
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