:root{
  --hero-bg:#1a222c; --brand:#14457a; --brand-dark:#0f3358;
  --accent:#1d5fa8; --accent-dark:#14457a; --accent-on-dark:#7cb3e8;
  --ink:#16212b; --muted:#5b6b7a; --rule:#dde5ec; --wash:#f1f5f9;
  --card:#ffffff; --page:#ffffff; --band:#f5f8fa;
  --maxw:1120px; --radius:10px;
  --sans:"Barlow","Helvetica Neue",Arial,sans-serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:var(--sans);color:var(--ink);background:var(--page);
  font-size:17px;line-height:1.62;-webkit-font-smoothing:antialiased}
img{max-width:100%;height:auto;display:block}
a{color:var(--brand);text-underline-offset:3px}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 22px}
h1,h2,h3,h4{line-height:1.18;margin:0 0 .5em;font-weight:700;letter-spacing:-.01em}
h1{font-size:clamp(2rem,4.4vw,3.15rem)}
h2{font-size:clamp(1.5rem,2.7vw,2.05rem);color:var(--brand-dark)}
h3{font-size:1.16rem}
p{margin:0 0 1.05em}
.lede{font-size:1.16rem;color:var(--muted)}
.eyebrow{text-transform:uppercase;letter-spacing:.13em;font-size:.75rem;font-weight:700;
  color:var(--accent-on-dark);margin:0 0 .7em}
/* header */
header.site{background:var(--hero-bg);position:sticky;top:0;z-index:40;
  border-bottom:1px solid rgba(255,255,255,.10)}
.bar{display:flex;align-items:center;gap:20px;min-height:66px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:#fff;font-weight:800;
  font-size:1.16rem;letter-spacing:-.02em;white-space:nowrap}
.logo .mark{width:30px;height:30px;flex:0 0 30px}
.logo span.lo{color:var(--accent-on-dark)}
nav.main{margin-left:auto;display:flex;gap:22px;align-items:center;flex-wrap:wrap}
nav.main a{color:#dbe6ef;text-decoration:none;font-size:.94rem;font-weight:600}
nav.main a:hover,nav.main a[aria-current=page]{color:#fff;text-decoration:underline}
nav.main a.btn{color:#fff}
.btn{display:inline-block;background:var(--accent);color:#fff;text-decoration:none;
  font-weight:700;padding:12px 22px;border-radius:var(--radius);border:0;cursor:pointer;
  font-size:1rem;font-family:inherit;line-height:1.25}
.btn:hover{background:var(--accent-dark)}
.btn.ghost{background:transparent;border:1.5px solid rgba(255,255,255,.55);color:#fff}
.btn.ghost:hover{background:rgba(255,255,255,.12)}
.btn.solidbrand{background:var(--brand);}
.btn.solidbrand:hover{background:var(--brand-dark)}
.btn.wide{width:100%;text-align:center}
/* hero */
.hero{background:var(--hero-bg);color:#fff;padding:64px 0 72px}
.hero h1{color:#fff;max-width:19ch}
.hero p.sub{font-size:1.2rem;color:#c3d3e2;max-width:60ch}
.hero .actions{display:flex;gap:14px;flex-wrap:wrap;margin-top:26px}
.hero .trust{margin-top:34px;padding-top:22px;border-top:1px solid rgba(255,255,255,.16);
  display:flex;gap:34px;flex-wrap:wrap;color:#b9cadb;font-size:.93rem}
.hero .trust b{color:#fff;display:block;font-size:1.02rem}
/* sections */
section{padding:56px 0}
section.band{background:var(--band);border-top:1px solid var(--rule);border-bottom:1px solid var(--rule)}
section.wash{background:var(--wash)}
.grid{display:grid;gap:22px}
.g2{grid-template-columns:repeat(auto-fit,minmax(300px,1fr))}
.g3{grid-template-columns:repeat(auto-fit,minmax(268px,1fr))}
.card{background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);padding:24px}
.card h3{margin-top:0;color:var(--brand-dark)}
.card p:last-child{margin-bottom:0}
.card .tag{display:inline-block;font-size:.72rem;font-weight:700;text-transform:uppercase;
  letter-spacing:.1em;color:var(--accent);margin-bottom:8px}
ul.ticks{list-style:none;padding:0;margin:0 0 1em}
ul.ticks li{padding-left:26px;position:relative;margin-bottom:.55em}
ul.ticks li::before{content:"";position:absolute;left:0;top:.55em;width:12px;height:7px;
  border-left:2.5px solid var(--accent);border-bottom:2.5px solid var(--accent);
  transform:rotate(-45deg)}
ol.steps{counter-reset:s;list-style:none;padding:0;margin:0}
ol.steps li{counter-increment:s;position:relative;padding-left:52px;margin-bottom:22px}
ol.steps li::before{content:counter(s);position:absolute;left:0;top:0;width:34px;height:34px;
  border-radius:50%;background:var(--brand);color:#fff;font-weight:700;display:flex;
  align-items:center;justify-content:center;font-size:1rem}
ol.steps li b{display:block;font-size:1.05rem}
table.spec{width:100%;border-collapse:collapse;font-size:.97rem}
table.spec th,table.spec td{text-align:left;padding:11px 12px;border-bottom:1px solid var(--rule);
  vertical-align:top}
table.spec th{background:var(--wash);color:var(--brand-dark);font-size:.86rem;
  text-transform:uppercase;letter-spacing:.06em}
.callout{border-left:4px solid var(--accent);background:var(--wash);padding:18px 22px;
  border-radius:0 var(--radius) var(--radius) 0}
.callout p:last-child{margin-bottom:0}
.split{display:grid;gap:34px;grid-template-columns:repeat(auto-fit,minmax(320px,1fr));align-items:start}
/* form */
.formwrap{background:var(--card);border:1px solid var(--rule);border-radius:var(--radius);
  padding:26px;box-shadow:0 2px 14px rgba(11,31,51,.06)}
.field{margin-bottom:16px}
.field label{display:block;font-weight:700;font-size:.92rem;margin-bottom:5px}
.field .hint{font-weight:400;color:var(--muted);font-size:.85rem}
.field input,.field select,.field textarea{width:100%;font-family:inherit;font-size:16px;
  padding:11px 12px;border:1.5px solid #c3d0db;border-radius:8px;background:#fff;color:var(--ink)}
.field input:focus,.field select:focus,.field textarea:focus{outline:3px solid rgba(0,0,0,.08);
  border-color:var(--brand)}
.field textarea{min-height:104px;resize:vertical}
.hp{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}
.formnote{font-size:.86rem;color:var(--muted);margin:12px 0 0}
/* footer */
footer.site{background:var(--hero-bg);color:#c2d2e1;padding:46px 0 28px;font-size:.94rem}
footer.site h4{color:#fff;font-size:.82rem;text-transform:uppercase;letter-spacing:.11em;margin-bottom:.9em}
footer.site a{color:#c2d2e1}
footer.site a:hover{color:#fff}
.fgrid{display:grid;gap:30px;grid-template-columns:repeat(auto-fit,minmax(210px,1fr))}
.legal{margin-top:32px;padding-top:20px;border-top:1px solid rgba(255,255,255,.14);
  font-size:.83rem;color:#93a8bc}
.legal p{margin:0 0 .5em}
.skip{position:absolute;left:-9999px;background:#fff;color:var(--ink);padding:10px 16px;z-index:99}
.skip:focus{left:12px;top:10px}
@media (max-width:640px){
  .bar{flex-wrap:wrap;padding:10px 0;min-height:0}
  nav.main{margin-left:0;width:100%;gap:16px;padding-bottom:6px}
  .hero{padding:44px 0 52px}
  section{padding:42px 0}
}

/* --- technical diagrams --- */
figure.dg{margin:26px 0;background:var(--card);border:1px solid var(--rule);
  border-radius:var(--radius);padding:20px 20px 16px}
figure.dg svg{width:100%;height:auto;display:block;overflow:visible}
figure.dg figcaption{margin-top:14px;font-size:.9rem;color:var(--muted);line-height:1.55}
figure.dg figcaption b{color:var(--ink)}
.dg-panels{display:grid;gap:20px;grid-template-columns:repeat(auto-fit,minmax(230px,1fr))}
.dg-panel h4{font-size:.82rem;text-transform:uppercase;letter-spacing:.09em;
  color:var(--brand-dark);margin:0 0 8px}
.dg-t{font-family:var(--sans);font-size:11.5px;font-weight:700;fill:var(--ink)}
.dg-l{font-family:var(--sans);font-size:10.5px;fill:var(--muted)}
.dg-a{font-family:var(--sans);font-size:10.5px;font-weight:700;fill:var(--accent)}
.dg-air{fill:var(--wash);stroke:var(--rule);stroke-width:1.5}
.dg-deck{fill:var(--brand)}
.dg-rail{fill:none;stroke:var(--brand);stroke-width:2.2;stroke-linecap:round;stroke-linejoin:round}
.dg-frame{fill:none;stroke:var(--brand);stroke-width:2;stroke-linejoin:round}
.dg-hi{fill:none;stroke:var(--accent);stroke-width:2.5;stroke-linecap:round}
.dg-hifill{fill:var(--accent)}
.dg-dim{fill:none;stroke:var(--muted);stroke-width:1;stroke-dasharray:4 3}
.dg-gnd{stroke:var(--ink);stroke-width:1.5;opacity:.35;stroke-linecap:round}
.dg-person{fill:none;stroke:var(--ink);stroke-width:2;opacity:.8;stroke-linecap:round}
.dg-head{fill:var(--ink);opacity:.8}