@font-face{font-family:Inter;src:url('/assets/fonts/InterLatin.woff2') format('woff2');font-style:normal;font-weight:100 900;font-display:swap}
:root{color-scheme:light;--paper:#f3f6f8;--white:#ffffff;--ink:#172b3b;--muted:#4b6070;--accent:#006b83;--accent-soft:#def3f7;--line:#bacbd6;--panel:#e7eff4;--grid:#dce6ed;--focus:#006b83;--radius:3px;--space:clamp(4rem,7vw,7rem)}
*{box-sizing:border-box}
html{scroll-padding-top:2rem;scrollbar-color:var(--muted) var(--paper)}
body{margin:0;background:var(--paper);color:var(--ink);font:400 1rem/1.65 Inter,Arial,sans-serif;-webkit-font-smoothing:antialiased}
::selection{background:var(--accent-soft);color:var(--ink)}
a{color:inherit;text-underline-offset:.22em;text-decoration-thickness:1px}
a:hover{color:var(--accent)}
button,summary{font:inherit;cursor:pointer}
button{color:inherit}
a,button,summary{-webkit-tap-highlight-color:var(--accent-soft)}
:focus-visible{outline:3px solid var(--focus);outline-offset:5px}
button[hidden]{display:none}
svg{display:block}
p{margin:0 0 1.25rem;max-width:70ch}
h1,h2,h3{line-height:1.08;font-weight:600;letter-spacing:-.035em;text-wrap:balance;margin:0}
h1{font-size:clamp(2.7rem,5.4vw,5.5rem)}
h2{font-size:clamp(1.85rem,3.2vw,3.1rem)}
h3{font-size:1.3rem;line-height:1.3;letter-spacing:-.02em}
em{font-style:normal;color:var(--accent)}
.wrap{width:min(1320px,calc(100% - 6rem));margin-inline:auto}
.skip{position:absolute;top:0;left:1rem;transform:translateY(-150%);padding:1rem;background:var(--ink);color:var(--white);z-index:5}
.skip:focus{transform:none}
.site-header{display:flex;align-items:center;justify-content:space-between;gap:2rem;min-height:110px;border-bottom:1px solid var(--line)}
.brand{display:inline-flex;align-items:center;gap:.7rem;text-decoration:none;line-height:1.12;min-height:48px;flex-shrink:0}
.brand>svg{stroke:var(--ink);stroke-width:1.6;fill:none}
.brand>svg .brand-signal{stroke:var(--accent)}
.brand span{font-size:1.05rem;letter-spacing:-.03em}
.brand strong{display:block;font-size:1.25rem;font-weight:700}
.desktop-nav{display:flex;align-items:center;gap:clamp(1rem,2.3vw,2.8rem)}
.desktop-nav a,.site-footer nav a{display:inline-flex;align-items:center;min-height:44px}
.desktop-nav a{text-decoration:none;font-size:.9rem;font-weight:600}
.desktop-nav a[aria-current]{text-decoration:underline;text-decoration-color:var(--accent);text-decoration-thickness:2px}
.desktop-nav a:last-child{border:1px solid var(--ink);padding:.4rem 1.1rem;border-radius:4px}
.mobile-nav{display:none}
.breadcrumbs{display:flex;flex-wrap:wrap;gap:.7rem;align-items:center;font-size:.8rem;color:var(--muted);min-height:56px;padding-block:.5rem}
.breadcrumbs a{display:inline-flex;align-items:center;min-height:44px}
.hero-grid{display:grid;grid-template-columns:1.2fr 1fr;align-items:start;gap:2.5rem 5rem;padding-block:2rem 4.5rem}
.hero-copy h1{margin:0;max-width:17ch}
.hero-intro{padding-top:.4rem}
.lead{font-size:clamp(1.15rem,1.6vw,1.4rem);line-height:1.55;max-width:44ch;color:var(--muted)}
.button{display:inline-flex;gap:1.4rem;align-items:center;justify-content:space-between;padding:1rem 1.3rem;min-height:54px;border-radius:4px;background:var(--ink);color:var(--white);text-decoration:none;font-size:.95rem;font-weight:600;margin-top:.7rem}
.button:hover{color:var(--white);background:var(--accent)}
.hero-detail{font-size:.85rem;color:var(--muted);margin-top:1.4rem}
.hero-diagram{grid-column:1/-1;margin:0;background-color:var(--white);background-image:linear-gradient(var(--grid) 1px,transparent 1px),linear-gradient(90deg,var(--grid) 1px,transparent 1px);background-size:32px 32px;padding:2.25rem 2rem 1.25rem;border:1px solid var(--ink);border-radius:var(--radius);display:grid;grid-template-columns:1fr auto;gap:0 2rem}
figure{margin:0;min-width:0}
.diagram{width:100%;height:auto;max-width:460px;margin:auto;overflow:visible;color:var(--ink)}
.diagram rect{fill:var(--white);stroke:var(--ink);stroke-width:1.1;rx:2px}
.diagram .accent-box{fill:var(--accent-soft);stroke:var(--accent)}
.diagram text{font-family:ui-monospace,Consolas,"Liberation Mono",monospace;letter-spacing:-.025em;font-size:16px;fill:var(--ink);font-weight:500}
.diagram .small{font-size:14px;fill:var(--muted);font-weight:400}
.diagram .wire{fill:none;stroke:var(--muted);stroke-width:1.4;stroke-linecap:round;stroke-linejoin:round}
.packet{transform:translate(180px,330px)}
.diagram .packet rect{fill:var(--accent);stroke:var(--white);stroke-width:1.5}
.packet path{stroke:var(--white);stroke-width:1.5;fill:none}
.node-pulse{fill:none;stroke:var(--accent);stroke-width:1.5}
.diagram[data-network="wide"] .packet{transform:translate(1026px,234px)}
figcaption{font-size:.85rem;color:var(--muted);line-height:1.55;margin-top:1.2rem;max-width:54ch}
.motion-toggle{display:block;background:transparent;border:1px solid var(--muted);padding:.5rem .8rem;min-height:44px;margin:1rem 0 0;border-radius:4px;font-size:.8rem}
.motion-toggle:hover{background:var(--white)}
.introduction{display:grid;grid-template-columns:1fr 1fr;gap:5rem;padding-block:var(--space);border-top:1px solid var(--line)}
.introduction p{max-width:47ch;font-size:1.1rem}
.library{padding-block:0 var(--space)}
.section-heading{display:flex;gap:2rem;align-items:end;justify-content:space-between;margin-bottom:3.5rem}
.section-heading>p{color:var(--muted);margin:0;min-width:20ch}
.guide-groups{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:3rem}
.guide-group h3{padding-bottom:1.5rem;border-bottom:2px solid var(--ink)}
.guide-link{display:flex;align-items:center;justify-content:space-between;gap:1rem;text-decoration:none;padding:1.4rem 0;min-height:92px;border-bottom:1px solid var(--line);line-height:1.4;font-weight:500}
.guide-link svg{flex-shrink:0;fill:none;stroke:var(--accent);stroke-width:1.5}
.guide-link:hover svg{transform:translateX(3px)}
.reading-strip{background:var(--panel);border-block:1px solid var(--line);padding-block:var(--space)}
.reading-strip>.wrap{display:grid;grid-template-columns:1.1fr 1fr;column-gap:5rem;row-gap:1rem}
.reading-strip h2{grid-row:span 2}
.reading-strip p{max-width:48ch}
.text-link{display:inline-flex;align-items:center;gap:1rem;min-height:44px;font-weight:600;width:fit-content}
.learn-more{display:grid;grid-template-columns:1fr 1fr;gap:5rem;padding-block:var(--space);align-items:start}
.learn-more h2{margin-bottom:1.5rem}
.form-slot{min-width:0}
.form-embed{min-height:var(--form-height)}
.form-embed iframe{display:block;max-width:100%}
.form-placeholder{min-height:280px;border:1px dashed var(--muted);border-radius:var(--radius);display:grid;place-items:center;padding:1.5rem}
.form-placeholder p{margin:0;color:var(--muted);text-align:center}
.sources{border-top:1px solid var(--line);padding-block:4rem var(--space)}
.sources h2{font-size:clamp(1.65rem,2.4vw,2.3rem);margin-bottom:1.5rem}
.sources p{color:var(--muted)}
.source-links{display:flex;flex-wrap:wrap;gap:.5rem 2rem}
.source-links a{display:inline-flex;align-items:center;min-height:44px}
.site-footer{background:var(--panel);border-top:1px solid var(--ink);padding-block:3rem}
.footer-top{display:flex;align-items:start;justify-content:space-between;gap:2rem;margin-bottom:2rem}
.footer-top p{font-weight:500}
.site-footer nav{display:flex;flex-wrap:wrap;gap:.5rem 2rem;margin-bottom:2rem}
.footer-note,.site-footer small{color:var(--muted);font-size:.85rem}
.article{padding-bottom:var(--space)}
.article-head{padding:2rem 0 3.5rem;max-width:1000px}
.article-head h1{font-size:clamp(2.6rem,5.5vw,5rem);max-width:20ch;margin-bottom:1.5rem}
.article-head .lead{max-width:58ch}
.notice{display:inline-block;font-size:.9rem;background:var(--accent-soft);padding:.8rem 1rem;border-radius:4px}
.article-layout{display:grid;grid-template-columns:230px minmax(0,1fr);gap:4rem;align-items:start}
.contents{border-top:1px solid var(--ink);padding-top:1rem;position:sticky;top:2rem}
.contents p{font-weight:600;font-size:.85rem;margin-bottom:1rem}
.contents a{display:flex;align-items:center;min-height:44px;padding:.5rem 0;color:var(--muted);font-size:.85rem;line-height:1.5;text-decoration:none}
.contents a:hover{text-decoration:underline;color:var(--accent)}
.article-body{min-width:0}
.explanation{padding-block:0 3.5rem;margin-bottom:3.5rem;border-bottom:1px solid var(--line);scroll-margin-top:2rem}
.explanation h2{font-size:clamp(1.65rem,2.8vw,2.4rem);margin-bottom:1.5rem;max-width:28ch}
.explanation p{max-width:70ch}
.with-diagram{display:grid;grid-template-columns:1.12fr minmax(270px,1fr);gap:2.5rem;align-items:start}
.explanation figure{background-color:var(--white);background-image:linear-gradient(var(--grid) 1px,transparent 1px),linear-gradient(90deg,var(--grid) 1px,transparent 1px);background-size:24px 24px;padding:1.2rem;border:1px solid var(--line);border-radius:var(--radius)}
.explanation .source{font-size:.85rem;color:var(--muted);margin-top:1.5rem}
.family-list{display:grid;grid-template-columns:1fr 1fr;gap:0 2.5rem;margin-top:2rem}
.family-list section{padding-block:1.5rem;border-top:1px solid var(--line);min-width:0}
.family-list h3{font-size:1.15rem;margin-bottom:.7rem}
.family-list p{margin-bottom:.7rem}
.supply{font-size:.9rem;color:var(--muted)}
.definitions{margin:0}
.definitions dt{font-weight:600;margin-top:1.2rem}
.definitions dd{margin:0 0 1.5rem;color:var(--muted);max-width:65ch}
.explanation ul{padding-left:1.3rem;max-width:65ch}
.explanation li{padding:.25rem 0 .5rem}
.next-guide h2{font-size:1.6rem;margin-bottom:1rem}
.tracking-frame{display:none;visibility:hidden}
@media(min-width:1500px){.with-diagram{grid-template-columns:1.2fr 1fr}
}
@media(max-width:1150px){.wrap{width:calc(100% - 4rem)}
.article-layout{grid-template-columns:190px minmax(0,1fr);gap:2.5rem}
.with-diagram{grid-template-columns:1fr}
.explanation figure{max-width:520px}
.guide-groups{gap:2rem}
}
@media(max-width:820px){.wrap{width:calc(100% - 3rem)}
.desktop-nav{display:none}
.site-header{min-height:90px;position:relative}
.mobile-nav{display:block}
.mobile-nav summary{min-width:70px;min-height:48px;display:flex;align-items:center;justify-content:center;border:1px solid var(--ink);border-radius:4px;list-style:none}
.mobile-nav summary::-webkit-details-marker{display:none}
.mobile-nav[open] summary{background:var(--panel)}
.mobile-nav nav{position:absolute;z-index:3;top:calc(100% - 1px);left:0;right:0;background:var(--paper);padding:1rem 1.5rem;box-shadow:0 12px 24px #172b3b1a;border:1px solid var(--line)}
.mobile-nav nav a{display:flex;align-items:center;min-height:48px}
.hero-copy h1{font-size:clamp(2.7rem,6vw,4rem)}
.hero-diagram{padding:1rem}
.introduction,.learn-more{gap:2.5rem}
.learn-more{grid-template-columns:1fr}
.guide-groups{grid-template-columns:1fr}
.guide-group{display:grid;grid-template-columns:1.2fr repeat(3,1fr);gap:1rem;border-top:1px solid var(--line);padding-top:1.5rem}
.guide-group h3{border:0;font-size:1.1rem}
.guide-link{padding:0 0 1.5rem;min-height:80px;font-size:.9rem;align-items:start}
.guide-link svg{width:18px;height:18px}
.article-layout{grid-template-columns:1fr;gap:2.5rem}
.contents{position:static;display:grid;grid-template-columns:1fr 1fr;gap:0 1.5rem;padding-block:1rem;border-bottom:1px solid var(--line)}
.contents p{grid-column:1/-1}
.with-diagram{grid-template-columns:1fr;gap:2rem}
.with-diagram h2{font-size:1.8rem}
.explanation figure{padding:.7rem}
.reading-strip>.wrap{gap:1.5rem 2.5rem}
}
@media(max-width:700px){.wrap{width:calc(100% - 2.5rem)}
.breadcrumbs{font-size:.75rem}
.hero-copy h1{font-size:clamp(2.8rem,12vw,4.5rem);max-width:13ch}
.hero-detail{margin-bottom:0}
.hero-diagram{padding:1.25rem}
.diagram{max-width:380px}
.introduction,.learn-more,.reading-strip>.wrap{grid-template-columns:1fr;gap:2rem}
.form-embed{min-height:0}
.introduction h2 br{display:none}
.section-heading{display:block;margin-bottom:2rem}
.section-heading p{margin-top:1.5rem}
.guide-group{grid-template-columns:1fr;gap:0;border:0;padding:0}
.guide-group h3{padding-bottom:1rem;border-bottom:2px solid var(--ink);font-size:1.25rem}
.guide-link{min-height:74px;padding:1.2rem 0;font-size:1rem;align-items:center}
.guide-groups{gap:2.8rem}
.reading-strip h2{grid-row:auto}
.reading-strip p{margin-bottom:0}
.sources{padding-top:3rem}
.footer-top{display:block}
.footer-top p{margin-top:2rem}
.site-footer nav{display:grid;grid-template-columns:1fr 1fr;gap:.5rem 1rem}
.article-head{padding:1rem 0 2rem}
.article-head h1{font-size:clamp(2.5rem,10vw,3.8rem)}
.contents{grid-template-columns:1fr;gap:0}
.with-diagram{grid-template-columns:1fr;gap:1.5rem}
.explanation{padding-bottom:2.8rem;margin-bottom:2.8rem}
.family-list{grid-template-columns:1fr}
.form-placeholder{min-height:240px}
}
.hero-diagram .diagram{grid-column:1/-1;max-width:none;width:100%}
.hero-diagram .diagram[data-network="compact"]{display:none}
.hero-diagram figcaption{margin-top:1rem;max-width:80ch}
.hero-diagram .motion-toggle{align-self:end;margin-top:.8rem;background:var(--white)}
.hero-diagram .small{font-size:15px;letter-spacing:.01em}
.hero-intro .lead{max-width:43ch}
.hero-copy h1{font-weight:650;letter-spacing:-.04em}
.article-head h1{font-weight:650}
.form-placeholder{border-style:solid;background:var(--white)}
.moved-page{padding-block:3rem 5rem;max-width:70ch}
.moved-page h1{font-size:2.5rem;margin-bottom:1.5rem}
@media(max-width:1150px){.hero-grid{gap:2rem 3rem}
}
@media(max-width:820px){.hero-grid{grid-template-columns:1fr 1fr;gap:1.5rem;padding-block:1.8rem 3rem}
.hero-diagram{padding:1.25rem}
.hero-diagram .diagram[data-network="wide"]{display:none}
.hero-diagram .diagram[data-network="compact"]{display:block;width:100%;max-width:420px}
.hero-diagram .small{font-size:14px}
}
@media(max-width:700px){.hero-grid{grid-template-columns:1fr;gap:1.5rem;padding-top:1rem}
.hero-copy h1{max-width:14ch;margin:0}
.hero-intro{padding:0}
.hero-intro .lead{font-size:1.1rem}
.hero-diagram{grid-template-columns:1fr;gap:0;padding:1.25rem .8rem}
.hero-diagram .motion-toggle{justify-self:start}
.hero-diagram figcaption{padding-inline:.35rem}
}
@media(prefers-reduced-motion:no-preference){
 a,button{transition:color .15s ease,background-color .15s ease}
.guide-link svg{transition:transform .2s ease}
 .motion-enabled [data-network] .packet{transform:none;offset-path:path("M180 48 L180 100 L70 136 L70 174 L180 230 L180 296 L70 350");offset-rotate:0deg;animation:transaction 12s linear infinite;animation-play-state:paused}
 .motion-enabled [data-network="compact"] .packet{animation-name:transaction-compact}
 .motion-enabled [data-network="wide"] .packet{offset-path:path("M104 164 L190 164 L190 144 L280 144 L280 116 L410 116 L535 116 L535 185 L707 185 L882 185 L882 234 L1026 234")}
 .motion-enabled .hero-diagram .wire{stroke-dasharray:1;animation:draw-route 12s linear infinite;animation-fill-mode:backwards;animation-play-state:paused}
 .motion-enabled .hero-diagram .stage-block{animation-delay:3s}
.motion-enabled .hero-diagram .stage-verify{animation-delay:6s}
 .motion-enabled [data-network] .node-pulse{transform-box:fill-box;transform-origin:center;animation:node-check 12s ease-out infinite;animation-play-state:paused}
 .motion-enabled [data-network] .pulse-verify{animation-delay:6s}
 .motion-enabled .motion-running .packet,.motion-enabled .motion-running .wire,.motion-enabled .motion-running .node-pulse{animation-play-state:running}
 .motion-paused .packet,.motion-paused .wire,.motion-paused .node-pulse,.motion-hidden .packet,.motion-hidden .wire,.motion-hidden .node-pulse{animation-play-state:paused!important}
 @keyframes transaction{0%,8%{offset-distance:0%}
30%,37%{offset-distance:32%}
61%,68%{offset-distance:65%}
90%,100%{offset-distance:100%}
}
 @keyframes transaction-compact{0%,8%{offset-distance:0%}30%,37%{offset-distance:32%}61%,68%{offset-distance:69.5%}90%,100%{offset-distance:100%}}
 @keyframes draw-route{0%{stroke-dashoffset:1}
22%,100%{stroke-dashoffset:0}
}
 @keyframes node-check{0%,22%,50%,100%{opacity:.55;transform:scale(1)}
30%{opacity:1;transform:scale(1.45)}
}
}