:root{
  --bg:#f7f9fc;
  --surface:#ffffff;
  --surface-2:#eef4f7;
  --ink:#0d1b2a;
  --muted:#566575;
  --line:#dbe4ea;
  --brand:#0a6f7f;
  --brand-2:#174a7e;
  --accent:#f2a93b;
  --ok:#18794e;
  --warn:#9a6700;
  --shadow:0 12px 30px rgba(17,38,58,.08);
  --radius:18px;
  --max:1180px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;background:var(--bg);color:var(--ink);line-height:1.65}
a{color:var(--brand-2);text-decoration:none}
a:hover{text-decoration:underline}
img{max-width:100%;display:block}
.wrap{width:min(calc(100% - 32px),var(--max));margin-inline:auto}
.site-header{position:sticky;top:0;z-index:50;background:rgba(247,249,252,.94);backdrop-filter:blur(14px);border-bottom:1px solid var(--line)}
.nav{min-height:72px;display:flex;align-items:center;justify-content:space-between;gap:24px}
.brand{display:flex;align-items:center;gap:12px;color:var(--ink);font-weight:800;text-decoration:none}
.brand-mark{width:42px;height:42px;border-radius:12px;background:linear-gradient(145deg,var(--brand-2),var(--brand));display:grid;place-items:center;color:#fff;font-size:18px;letter-spacing:.05em;box-shadow:var(--shadow)}
.brand-text small{display:block;font-weight:600;color:var(--muted);font-size:11px;letter-spacing:.07em;text-transform:uppercase}
.nav-links{display:flex;align-items:center;gap:20px;font-weight:650;font-size:14px}
.nav-links a{color:var(--ink)}
.nav-actions{display:flex;align-items:center;gap:10px}
.btn{appearance:none;border:0;border-radius:12px;padding:11px 16px;font:inherit;font-weight:750;cursor:pointer;display:inline-flex;align-items:center;justify-content:center;gap:8px;text-decoration:none}
.btn:hover{text-decoration:none}
.btn-primary{background:var(--brand-2);color:#fff}
.btn-secondary{background:var(--surface);color:var(--ink);border:1px solid var(--line)}
.menu-btn{display:none}
.hero{padding:88px 0 64px;background:radial-gradient(circle at 85% 15%,rgba(10,111,127,.14),transparent 28%),radial-gradient(circle at 15% 0%,rgba(242,169,59,.12),transparent 26%)}
.hero-grid{display:grid;grid-template-columns:1.25fr .75fr;gap:54px;align-items:center}
.eyebrow{display:inline-flex;align-items:center;gap:8px;padding:7px 11px;border:1px solid var(--line);border-radius:999px;background:rgba(255,255,255,.78);font-size:12px;font-weight:800;letter-spacing:.07em;text-transform:uppercase;color:var(--brand-2)}
h1{font-size:clamp(42px,7vw,76px);line-height:1.02;letter-spacing:-.045em;margin:18px 0 22px}
.hero p{font-size:19px;color:var(--muted);max-width:720px}
.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:28px}
.hero-panel{background:linear-gradient(160deg,#0d2a47,#0b6c78);color:#fff;border-radius:28px;padding:30px;box-shadow:0 24px 55px rgba(10,43,72,.22)}
.hero-panel h2{margin-top:0;font-size:22px}
.acronym{display:grid;grid-template-columns:auto 1fr;gap:8px 14px;margin-top:22px}
.acronym strong{font-size:24px;color:#ffd58b}
.acronym span{align-self:center}
.section{padding:70px 0}
.section.alt{background:var(--surface)}
.section-head{display:flex;justify-content:space-between;gap:24px;align-items:end;margin-bottom:28px}
.section-head h2{font-size:34px;line-height:1.15;letter-spacing:-.025em;margin:0}
.section-head p{margin:0;color:var(--muted);max-width:620px}
.grid{display:grid;gap:20px}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-4{grid-template-columns:repeat(4,1fr)}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:24px;box-shadow:0 4px 15px rgba(16,43,67,.04)}
.card:hover{transform:translateY(-2px);box-shadow:var(--shadow);transition:.18s ease}
.card .tag{display:inline-block;font-size:11px;letter-spacing:.08em;text-transform:uppercase;font-weight:850;color:var(--brand);margin-bottom:12px}
.card h3{margin:0 0 10px;font-size:21px;line-height:1.25}
.card p{margin:0;color:var(--muted)}
.topic-icon{width:44px;height:44px;border-radius:13px;background:var(--surface-2);display:grid;place-items:center;font-weight:900;color:var(--brand-2);margin-bottom:16px}
.callout{border-left:4px solid var(--accent);background:#fff8e8;padding:18px 20px;border-radius:0 14px 14px 0;color:#5f4a1d}
.cta{background:linear-gradient(135deg,#0d2a47,#174a7e);color:#fff;border-radius:26px;padding:36px;display:flex;align-items:center;justify-content:space-between;gap:30px}
.cta h2{margin:0 0 8px}.cta p{margin:0;color:#dce8f4;max-width:720px}.cta .btn{background:#fff;color:#123453}
.site-footer{padding:46px 0 30px;background:#0a1826;color:#d6e2ec}
.footer-grid{display:grid;grid-template-columns:1.4fr repeat(3,1fr);gap:30px}
.site-footer h4{color:#fff;margin:0 0 12px}.site-footer a{color:#d6e2ec}.site-footer p{color:#9fb1c1}.fineprint{border-top:1px solid rgba(255,255,255,.12);margin-top:30px;padding-top:20px;font-size:12px;color:#93a6b5}
.page-hero{padding:60px 0 36px}.page-hero h1{font-size:clamp(38px,6vw,62px);margin:12px 0 16px}.page-hero p{font-size:18px;color:var(--muted);max-width:800px}
.article-layout{display:grid;grid-template-columns:minmax(0,1fr) 280px;gap:42px;align-items:start}
.article{background:var(--surface);border:1px solid var(--line);border-radius:22px;padding:clamp(24px,5vw,48px)}
.article h2{margin-top:38px;line-height:1.2}.article h3{margin-top:28px}.article p,.article li{color:#314253}.article .lead{font-size:20px;color:#223547}.article-meta{display:flex;gap:14px;flex-wrap:wrap;color:var(--muted);font-size:13px;margin-bottom:26px}.sidebar{position:sticky;top:96px}.toc{background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:20px}.toc strong{display:block;margin-bottom:10px}.toc a{display:block;padding:7px 0;font-size:14px}.tool-shell{background:var(--surface);border:1px solid var(--line);border-radius:22px;padding:28px;box-shadow:var(--shadow)}
.tool-row{display:grid;grid-template-columns:70px 1fr 1fr 1fr 1fr auto;gap:10px;margin-bottom:10px;align-items:center}.tool-row input,.tool-row select,.field input,.field select{width:100%;padding:11px 12px;border:1px solid #cfdbe4;border-radius:10px;background:#fff;font:inherit}.tool-row.head{font-size:12px;font-weight:800;text-transform:uppercase;letter-spacing:.05em;color:var(--muted)}.tool-row.head>div{text-align:left}.remove-row{border:0;background:#f8e9e9;color:#862020;border-radius:10px;width:38px;height:38px;cursor:pointer;font-weight:800}.results{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-top:24px}.result{background:var(--surface-2);border-radius:14px;padding:16px}.result small{display:block;color:var(--muted);font-weight:700}.result strong{display:block;font-size:22px;margin-top:4px}.note{font-size:13px;color:var(--muted)}
.search-overlay{position:fixed;inset:0;background:rgba(7,18,28,.55);display:none;z-index:100;padding:80px 20px}.search-overlay.open{display:block}.search-box{max-width:760px;margin:0 auto;background:#fff;border-radius:18px;padding:18px;box-shadow:0 30px 80px rgba(0,0,0,.25)}.search-box input{width:100%;padding:15px 16px;font-size:18px;border:1px solid var(--line);border-radius:12px}.search-results{margin-top:12px;max-height:55vh;overflow:auto}.search-item{display:block;padding:14px;border-radius:10px;color:var(--ink)}.search-item:hover{background:var(--surface-2);text-decoration:none}.search-item small{display:block;color:var(--muted)}
.badge{display:inline-flex;padding:4px 8px;border-radius:999px;background:var(--surface-2);font-size:11px;font-weight:800;color:var(--brand-2)}
@media(max-width:900px){.nav-links{display:none;position:absolute;top:72px;left:16px;right:16px;flex-direction:column;align-items:stretch;background:#fff;border:1px solid var(--line);border-radius:16px;padding:18px;box-shadow:var(--shadow)}.nav-links.open{display:flex}.menu-btn{display:inline-flex}.hero-grid,.article-layout{grid-template-columns:1fr}.grid-4{grid-template-columns:repeat(2,1fr)}.grid-3{grid-template-columns:1fr}.sidebar{position:static}.footer-grid{grid-template-columns:1fr 1fr}.tool-row{grid-template-columns:1fr 1fr}.tool-row.head{display:none}.results{grid-template-columns:1fr 1fr}}
@media(max-width:620px){.nav-actions .search-label{display:none}.hero{padding-top:54px}.grid-4,.footer-grid,.results{grid-template-columns:1fr}.section{padding:54px 0}.section-head,.cta{align-items:flex-start;flex-direction:column}.tool-row{grid-template-columns:1fr}.tool-row input,.tool-row select{min-height:44px}}

/* V0.2 tool components */
.tool-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}
.field{display:flex;flex-direction:column;gap:7px}
.field label{font-weight:800;font-size:13px;color:#314253}
.field small{color:var(--muted);font-size:12px}
.field.full{grid-column:1/-1}
.tool-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:20px}
.results.results-3{grid-template-columns:repeat(3,1fr)}
.results.results-5{grid-template-columns:repeat(5,1fr)}
.result.emphasis{background:#e9f4f5;border:1px solid #c7e2e6}
.result.warning{background:#fff7e3;border:1px solid #f0d59a}
.formula{font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,"Liberation Mono",monospace;background:#f4f7f9;border:1px solid var(--line);border-radius:12px;padding:14px 16px;overflow:auto}
.tool-diagram{margin-top:22px;background:#f7fafc;border:1px solid var(--line);border-radius:16px;padding:20px}
.tool-diagram svg{width:100%;height:auto;max-height:260px}
.info-strip{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-top:18px}
.info-chip{background:#f7fafc;border:1px solid var(--line);border-radius:13px;padding:14px}
.info-chip strong{display:block;margin-bottom:4px}
.status-line{margin-top:16px;padding:13px 15px;border-radius:12px;background:#eef4f7;color:#314253;font-weight:700}
.status-line.good{background:#eaf6ef;color:#17643f}
.status-line.caution{background:#fff6df;color:#795600}
.source-list{margin:12px 0 0;padding-left:20px;color:#314253}
.version-pill{display:inline-flex;padding:4px 8px;border-radius:999px;background:#0d2a47;color:#fff;font-size:11px;font-weight:850;letter-spacing:.04em}
@media(max-width:900px){.tool-grid,.info-strip{grid-template-columns:1fr}.results.results-3,.results.results-5{grid-template-columns:1fr 1fr}}
@media(max-width:620px){.results.results-3,.results.results-5{grid-template-columns:1fr}}

/* V0.3 knowledge library */
.article-card{display:flex;flex-direction:column;min-height:220px}
.article-card .tag{align-self:flex-start}
.article-card h3{margin-top:14px}
.filter-bar{display:flex;gap:10px;flex-wrap:wrap;margin-bottom:28px}
.filter-chip{border:1px solid var(--line);background:var(--surface);color:var(--ink);padding:9px 13px;border-radius:999px;font:inherit;font-size:13px;font-weight:800;cursor:pointer}
.filter-chip.active,.filter-chip:hover{background:var(--brand-2);border-color:var(--brand-2);color:#fff}
.guide-filter-card[hidden]{display:none}
.empty-filter{padding:24px;border:1px dashed var(--line);border-radius:16px;color:var(--muted);text-align:center}
.related-guides{margin-top:42px;padding-top:28px;border-top:1px solid var(--line)}
.mini-link{display:flex;justify-content:space-between;gap:14px;padding:13px 0;border-bottom:1px solid var(--line);color:var(--ink)}
.mini-link span{color:var(--muted);font-size:13px;text-align:right}
.side-tool{margin-top:14px}
.hero-stats{display:flex;gap:26px;flex-wrap:wrap;margin-top:32px}
.hero-stats div{display:flex;flex-direction:column}
.hero-stats strong{font-size:28px;line-height:1;color:var(--brand-2)}
.hero-stats span{font-size:12px;color:var(--muted);margin-top:6px;font-weight:700}
.center-action{text-align:center;margin-top:28px}
@media(max-width:620px){.mini-link{flex-direction:column}.mini-link span{text-align:left}.hero-stats{gap:18px}}


/* V0.4 materials, visual learning and SEO polish */
:root{--blueprint:#dfeaf2;--metal:#6c7f90;--polymer:#6d4ca6}
.hero{position:relative;overflow:hidden}
.hero:before{content:"";position:absolute;inset:0;pointer-events:none;opacity:.34;background-image:linear-gradient(var(--blueprint) 1px,transparent 1px),linear-gradient(90deg,var(--blueprint) 1px,transparent 1px);background-size:32px 32px;mask-image:linear-gradient(to right,transparent 0%,rgba(0,0,0,.45) 45%,rgba(0,0,0,.7) 100%)}
.hero-grid{position:relative;z-index:1}
.visual-panel{background:linear-gradient(160deg,#0d2a47,#0b6c78);color:#fff;border-radius:28px;padding:18px;box-shadow:0 24px 55px rgba(10,43,72,.22)}
.visual-panel img{border-radius:18px;background:#f7fbfd;border:1px solid rgba(255,255,255,.18)}
.visual-panel .caption{font-size:12px;color:#cfe3ec;padding:12px 8px 4px;margin:0}
.trust-bar{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin-top:28px}
.trust-item{background:rgba(255,255,255,.74);border:1px solid var(--line);border-radius:14px;padding:14px}
.trust-item strong{display:block;color:var(--brand-2);font-size:14px}.trust-item span{font-size:12px;color:var(--muted)}
.article-figure{margin:28px 0;background:#f8fbfd;border:1px solid var(--line);border-radius:18px;padding:18px}
.article-figure img{width:100%;max-height:390px;object-fit:contain}
.article-figure figcaption{font-size:12px;color:var(--muted);margin-top:10px}
.breadcrumbs{font-size:12px;color:var(--muted);margin-bottom:12px}.breadcrumbs a{color:var(--muted)}
.author-box{display:flex;gap:14px;align-items:flex-start;border:1px solid var(--line);background:#f8fbfd;border-radius:15px;padding:15px;margin:0 0 26px}
.author-avatar{flex:0 0 38px;width:38px;height:38px;border-radius:50%;background:linear-gradient(145deg,var(--brand-2),var(--brand));display:grid;place-items:center;color:#fff;font-weight:900;font-size:13px}
.author-box strong{display:block}.author-box p{margin:3px 0 0;font-size:12px;color:var(--muted)}
.material-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.material-card{display:flex;flex-direction:column;min-height:230px}
.material-card .material-symbol{font-size:34px;font-weight:900;letter-spacing:-.04em;color:var(--brand-2)}
.material-card .material-meta{display:flex;gap:7px;flex-wrap:wrap;margin:10px 0 14px}
.material-chip{display:inline-flex;padding:4px 8px;border-radius:999px;background:var(--surface-2);font-size:10px;font-weight:850;color:var(--brand-2);text-transform:uppercase;letter-spacing:.04em}
.material-chip.metal{background:#edf0f3;color:#536676}.material-chip.polymer{background:#f0ebf8;color:#65449d}
.property-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px;margin:22px 0}
.property-card{border:1px solid var(--line);border-radius:14px;padding:16px;background:#fbfdfe}
.property-card small{display:block;color:var(--muted);font-weight:800;text-transform:uppercase;letter-spacing:.05em;font-size:10px}.property-card strong{font-size:18px;display:block;margin-top:4px}
.rating-row{display:grid;grid-template-columns:150px 1fr auto;align-items:center;gap:12px;padding:9px 0;border-bottom:1px solid var(--line)}
.rating-bar{height:8px;background:#e8eef2;border-radius:999px;overflow:hidden}.rating-fill{height:100%;background:linear-gradient(90deg,var(--brand),var(--brand-2));border-radius:999px}
.compare-table{width:100%;border-collapse:collapse;margin-top:24px}.compare-table th,.compare-table td{text-align:left;padding:13px;border-bottom:1px solid var(--line);vertical-align:top}.compare-table th{color:var(--muted);font-size:12px;text-transform:uppercase;letter-spacing:.05em}.compare-table td:nth-child(n+2){font-weight:650}
.material-hero{display:grid;grid-template-columns:1fr 330px;gap:28px;align-items:start}.material-summary{background:linear-gradient(145deg,#0d2a47,#0a6f7f);color:#fff;border-radius:20px;padding:24px}.material-summary h2{margin:0 0 14px}.material-summary dl{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:0}.material-summary dt{font-size:11px;text-transform:uppercase;letter-spacing:.06em;color:#bdd5df}.material-summary dd{margin:2px 0 0;font-weight:800}
.glossary-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px}.glossary-term{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:18px}.glossary-term dt{font-weight:900}.glossary-term dd{margin:5px 0 0;color:var(--muted)}
.launch-check{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.launch-check .card{min-height:160px}
.kicker-row{display:flex;gap:8px;flex-wrap:wrap;margin-top:14px}
.kicker{font-size:11px;font-weight:800;border:1px solid var(--line);padding:5px 8px;border-radius:999px;background:#fff}
@media(max-width:1000px){.material-grid{grid-template-columns:repeat(3,1fr)}.material-hero{grid-template-columns:1fr}.trust-bar{grid-template-columns:repeat(2,1fr)}}
@media(max-width:760px){.material-grid{grid-template-columns:repeat(2,1fr)}.property-grid,.glossary-grid,.launch-check{grid-template-columns:1fr}.rating-row{grid-template-columns:110px 1fr auto}}
@media(max-width:520px){.material-grid,.trust-bar{grid-template-columns:1fr}.material-summary dl{grid-template-columns:1fr}.compare-table{font-size:13px}.compare-table th,.compare-table td{padding:10px 8px}}

/* V0.5 interactive decision tools and downloads */
.process-results{margin-top:22px;display:grid;gap:14px}.process-result{display:grid;grid-template-columns:46px 1fr;gap:15px;border:1px solid var(--line);background:#fff;border-radius:16px;padding:16px}.process-rank{width:40px;height:40px;border-radius:12px;display:grid;place-items:center;background:#0d2a47;color:white;font-weight:900}.process-title{display:flex;justify-content:space-between;gap:12px;align-items:center}.process-title span{font-size:12px;color:var(--muted);font-weight:800}.process-copy p{margin:8px 0}.score-bar{height:8px;background:#e7eef2;border-radius:999px;overflow:hidden;margin-top:9px}.score-bar i{display:block;height:100%;background:linear-gradient(90deg,var(--brand),var(--brand-2));border-radius:999px}.review-summary{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;margin:22px 0}.review-summary div{border:1px solid var(--line);background:#f8fbfd;border-radius:14px;padding:13px}.review-summary small{display:block;color:var(--muted);font-weight:800}.review-summary strong{font-size:22px;color:var(--brand-2)}.checklist{display:grid;gap:9px}.check-row{display:grid;grid-template-columns:34px 1fr 150px;align-items:center;gap:12px;border:1px solid var(--line);border-radius:12px;padding:11px;background:#fff}.check-num{width:28px;height:28px;border-radius:9px;background:#eef4f7;display:grid;place-items:center;font-size:12px;font-weight:900;color:var(--brand-2)}.check-text{font-size:14px;font-weight:650}.check-status{min-height:38px}.material-find-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:14px;margin-top:18px}.material-find-card{border:1px solid var(--line);border-radius:16px;padding:17px;background:#fff;color:var(--ink);display:grid;grid-template-columns:1fr 220px;gap:14px}.material-find-card:hover{text-decoration:none;border-color:#a9cbd2;box-shadow:var(--shadow)}.material-find-card h3{margin:8px 0 5px}.material-find-card p{margin:0;color:var(--muted);font-size:12px}.mini-ratings{display:grid;gap:4px;font-size:11px;color:var(--muted)}.mini-ratings span{display:flex;justify-content:space-between;gap:8px}.mini-ratings b{letter-spacing:1px;color:var(--brand-2)}.download-card strong{margin-top:auto;color:var(--brand-2)}.download-card{min-height:220px}.workflow-strip{display:grid;grid-template-columns:repeat(4,1fr);gap:12px}.workflow-step{border:1px solid var(--line);background:#fff;border-radius:15px;padding:16px;position:relative}.workflow-step em{display:inline-grid;place-items:center;width:28px;height:28px;border-radius:8px;background:#0d2a47;color:#fff;font-style:normal;font-weight:900;font-size:12px}.workflow-step h3{margin:10px 0 6px}.workflow-step p{margin:0;color:var(--muted);font-size:13px}
@media(max-width:900px){.review-summary,.workflow-strip{grid-template-columns:repeat(2,1fr)}.material-find-card{grid-template-columns:1fr}.check-row{grid-template-columns:34px 1fr}.check-status{grid-column:2}}
@media(max-width:620px){.review-summary,.workflow-strip,.material-find-grid{grid-template-columns:1fr}.process-result{grid-template-columns:1fr}.process-title{align-items:flex-start;flex-direction:column}.check-row{grid-template-columns:1fr}.check-status{grid-column:1}.check-num{display:none}}


/* V0.6 design handbook, drawing and joint-reference tools */
.handbook-map{display:grid;grid-template-columns:repeat(5,1fr);gap:12px;margin-top:26px}.handbook-node{background:#fff;border:1px solid var(--line);border-radius:16px;padding:17px;position:relative}.handbook-node b{display:grid;place-items:center;width:32px;height:32px;border-radius:10px;background:var(--brand-2);color:#fff;margin-bottom:12px}.handbook-node h3{font-size:17px;margin:0 0 7px}.handbook-node p{font-size:12px;color:var(--muted);margin:0}.handbook-chapter{display:grid;grid-template-columns:100px 1fr;gap:24px;align-items:start;padding:24px 0;border-bottom:1px solid var(--line)}.chapter-num{font-size:52px;font-weight:950;line-height:1;color:#d7e4eb;letter-spacing:-.05em}.chapter-links{display:grid;grid-template-columns:repeat(2,1fr);gap:8px 20px;margin-top:14px}.chapter-links a{padding:9px 0;border-bottom:1px solid var(--line);font-weight:700}.symbol-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:18px}.symbol-card{border:1px solid var(--line);background:#fff;border-radius:14px;padding:15px;cursor:pointer;text-align:left;font:inherit}.symbol-card:hover,.symbol-card.active{border-color:#8dbbc4;background:#eef8f8}.symbol-card strong{display:block}.symbol-card small{color:var(--muted)}.fcf-preview{margin-top:18px;border:1px solid var(--line);border-radius:14px;background:#f8fbfd;padding:18px}.fcf{display:inline-flex;align-items:stretch;border:2px solid #243847;background:#fff;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-weight:800}.fcf span{padding:7px 10px;border-right:1px solid #243847}.fcf span:last-child{border-right:0}.reference-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px}.reference-sheet{border:1px solid var(--line);border-radius:18px;background:#fff;padding:22px}.reference-sheet h3{margin:0 0 8px}.reference-table{width:100%;border-collapse:collapse}.reference-table th,.reference-table td{border-bottom:1px solid var(--line);padding:11px 9px;text-align:left;vertical-align:top}.reference-table th{font-size:11px;text-transform:uppercase;letter-spacing:.05em;color:var(--muted)}.decision-line{display:grid;grid-template-columns:1fr auto;gap:12px;padding:12px 0;border-bottom:1px solid var(--line);align-items:center}.decision-line select{min-width:145px;padding:9px;border:1px solid var(--line);border-radius:9px;background:#fff}.joint-visual{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:18px}.joint-visual div{border:1px solid var(--line);background:#f8fbfd;border-radius:13px;padding:14px}.joint-visual strong{display:block;color:var(--brand-2)}.print-toolbar{display:flex;justify-content:flex-end;gap:10px;margin-bottom:18px}.ref-sheet-page{background:#fff;border:1px solid var(--line);border-radius:18px;padding:32px}.ref-sheet-page h1{font-size:36px}.ref-sheet-page h2{font-size:22px;margin-top:28px}.ref-columns{display:grid;grid-template-columns:repeat(2,1fr);gap:24px}.ref-box{border:1px solid var(--line);border-radius:12px;padding:14px}.ref-box h3{font-size:15px;margin:0 0 8px}.ref-box p,.ref-box li{font-size:12px;color:#314253}.micro{font-size:11px;color:var(--muted)}
@media(max-width:1000px){.handbook-map{grid-template-columns:repeat(3,1fr)}.symbol-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:760px){.handbook-map,.reference-grid,.joint-visual,.ref-columns{grid-template-columns:1fr}.handbook-chapter{grid-template-columns:1fr}.chapter-num{font-size:34px}.chapter-links{grid-template-columns:1fr}.symbol-grid{grid-template-columns:1fr}}
@media print{.site-header,.site-footer,.search-overlay,.print-toolbar,.page-hero{display:none!important}body{background:#fff;color:#000}.wrap{width:100%;max-width:none}.section{padding:0}.ref-sheet-page{border:0;padding:0}.reference-table th,.reference-table td{padding:7px 5px}.ref-box{break-inside:avoid}.micro{color:#444}}

/* V0.7 engineering-analysis additions */
.tool-figure{margin:0 0 24px;padding:16px;background:var(--surface-2);border:1px solid var(--line);border-radius:16px}.tool-figure img{width:100%;max-height:260px;object-fit:contain}.formula-toolbar{display:flex;gap:18px;align-items:center;justify-content:space-between;margin-bottom:18px}.formula-toolbar input{flex:1;max-width:720px;padding:14px 16px;border:1px solid var(--line);border-radius:12px;background:var(--surface);font:inherit}.table-scroll{overflow:auto;border:1px solid var(--line);border-radius:16px;background:var(--surface)}.formula-table{width:100%;border-collapse:collapse;min-width:800px}.formula-table th,.formula-table td{padding:14px 16px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}.formula-table th{position:sticky;top:0;background:var(--surface-2);z-index:1}.formula-table code,.reference-sheet code{font-size:.96em;background:var(--surface-2);padding:2px 6px;border-radius:6px;color:var(--ink)}.empty-state{padding:28px;text-align:center;color:var(--muted)}.reference-title{display:flex;justify-content:space-between;gap:24px;align-items:flex-start;border-bottom:3px solid var(--ink);padding-bottom:18px;margin-bottom:24px}.reference-title h1{margin:.2rem 0 0}.reference-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.reference-grid section{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px}.reference-grid h2{font-size:1.1rem;margin-top:0}.reference-grid ul{padding-left:20px}.results-4{grid-template-columns:repeat(4,minmax(0,1fr))}@media(max-width:760px){.formula-toolbar{align-items:stretch;flex-direction:column}.formula-toolbar input{max-width:none}.reference-grid,.results-4{grid-template-columns:1fr}.reference-title{display:block}}@media print{.print-hide,.site-header,.site-footer,.search-overlay{display:none!important}.reference-sheet{padding:0}.reference-sheet .wrap{width:100%;max-width:none}.reference-grid section{break-inside:avoid}.reference-title{margin-top:0}}

/* V0.8 machine-design additions */
.machine-flow{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:10px;align-items:stretch}.machine-flow>div{padding:14px;border:1px solid var(--line);background:var(--surface);border-radius:14px;text-align:center}.machine-flow strong{display:block;margin-bottom:4px}.center-action{display:flex;justify-content:center;margin-top:24px}@media(max-width:820px){.machine-flow{grid-template-columns:1fr 1fr}}@media(max-width:520px){.machine-flow{grid-template-columns:1fr}}


/* V0.9 discoverability, credibility, accessibility and ad-readiness */
.skip-link{position:fixed;left:16px;top:-60px;z-index:999;background:#fff;color:var(--ink);padding:10px 14px;border:2px solid var(--brand-2);border-radius:10px;font-weight:800;box-shadow:var(--shadow)}
.skip-link:focus{top:12px}.topic-resource-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin-top:26px}.topic-resource{display:flex;flex-direction:column}.topic-resource .card-link{margin-top:auto;padding-top:14px;font-weight:800}.topic-intro{max-width:850px}.topic-intro h2{font-size:34px;margin-bottom:8px}.topic-intro p{font-size:18px;color:var(--muted)}
.author-hero-grid{display:grid;grid-template-columns:1.2fr .8fr;gap:40px;align-items:center}.author-profile-card{background:linear-gradient(145deg,#0d2a47,#0b6c78);color:white;border-radius:24px;padding:28px;box-shadow:var(--shadow)}.author-profile-card p{color:#d8e5ee}.author-avatar-large{width:74px;height:74px;font-size:24px;margin-bottom:18px}.author-callout{display:grid;grid-template-columns:70px 1fr;gap:20px;border:1px solid var(--line);background:#f8fbfd;border-radius:20px;padding:24px;margin-bottom:30px;align-items:start}.author-callout h2{margin:6px 0 8px}
.article-references{margin-top:36px;padding:22px;border:1px solid var(--line);border-radius:16px;background:#f8fbfd}.article-references h2{margin-top:0}.reference-actions{display:flex;flex-wrap:wrap;gap:8px}.reference-actions a{display:inline-flex;padding:7px 10px;border-radius:999px;background:#fff;border:1px solid var(--line);font-size:12px;font-weight:800}.standards-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px;margin-top:28px}.standards-grid section{border:1px solid var(--line);background:#fff;border-radius:18px;padding:22px}.standards-grid h2{font-size:21px;margin:10px 0}.standards-grid li{margin-bottom:7px;color:#314253}
.trust-editorial{display:grid;grid-template-columns:1.25fr .75fr;gap:34px;align-items:center;border:1px solid var(--line);background:#fff;border-radius:24px;padding:30px}.trust-editorial h2{font-size:34px;margin:12px 0}.trust-editorial p{color:var(--muted)}.editorial-metrics{display:grid;grid-template-columns:repeat(2,1fr);gap:12px}.editorial-metrics div{padding:16px;border-radius:14px;background:var(--surface-2)}.editorial-metrics strong{display:block;font-size:27px;color:var(--brand-2)}.editorial-metrics span{font-size:12px;color:var(--muted)}
.article a:focus-visible,.btn:focus-visible,.nav-links a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid rgba(242,169,59,.75);outline-offset:3px}.search-open{overflow:hidden}
@media(max-width:900px){.topic-resource-grid,.standards-grid,.author-hero-grid,.trust-editorial{grid-template-columns:1fr}.editorial-metrics{grid-template-columns:repeat(2,1fr)}}
@media(max-width:620px){.topic-resource-grid,.standards-grid,.editorial-metrics{grid-template-columns:1fr}.author-callout{grid-template-columns:1fr}.trust-editorial{padding:22px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important;animation:none!important}}