/* ============================================================================
   1722 — site.css · "Titleblock — Warm Graphite & Copper Signal"
   Warm graphite base · engineering-paper light mode · one copper signal accent.
   Dark is the signature default; prefers-color-scheme:light and a manual toggle
   both switch to the paper theme. Radius 0. Hairlines do the structural work.
   ========================================================================== */

/* ---- Tokens: dark (default / signature) --------------------------------- */
:root{
  --bg:#15181B; --surface:#1E2327; --line:#2D343A;
  --fg:#E7E4DC; --muted:#8B949C;
  --accent:#B65B33;          /* copper — rules/borders/dots/large marks ONLY */
  --accent-text:#E88A3C;     /* amber-LED — accent TEXT / links / focus */
  --sel:#B65B33; --sel-fg:#15181B;
  --grid-op:0.14;

  --maxw:1200px; --measure:68ch;
  --f-display:'Archivo',system-ui,sans-serif;
  --f-body:'IBM Plex Sans',system-ui,sans-serif;
  --f-mono:'IBM Plex Mono',ui-monospace,SFMono-Regular,Menlo,monospace;

  --s1:4px; --s2:8px; --s3:12px; --s4:16px; --s5:24px; --s6:32px;
  --s7:48px; --s8:64px; --s9:96px; --s10:128px;
  --sec:clamp(64px,10vw,120px);           /* vertical rhythm between sections */
  --pad-inline:clamp(20px,5vw,48px);
}
/* prefers light, unless the user forced dark via the toggle */
@media (prefers-color-scheme: light){
  :root:not([data-theme="dark"]){
    --bg:#F3F1EA; --surface:#FBFAF6; --line:#D9D5CB;
    --fg:#191C1F; --muted:#5C6169;
    --accent:#B65B33; --accent-text:#9E4A26;
    --sel:#B65B33; --sel-fg:#F3F1EA; --grid-op:0.16;
  }
}
/* explicit toggle wins in both directions */
:root[data-theme="light"]{
  --bg:#F3F1EA; --surface:#FBFAF6; --line:#D9D5CB;
  --fg:#191C1F; --muted:#5C6169;
  --accent:#B65B33; --accent-text:#9E4A26;
  --sel:#B65B33; --sel-fg:#F3F1EA; --grid-op:0.16;
}
:root[data-theme="dark"]{
  --bg:#15181B; --surface:#1E2327; --line:#2D343A;
  --fg:#E7E4DC; --muted:#8B949C;
  --accent:#B65B33; --accent-text:#E88A3C;
  --sel:#B65B33; --sel-fg:#15181B; --grid-op:0.14;
}

/* ---- Reset -------------------------------------------------------------- */
*,*::before,*::after{box-sizing:border-box}
*{margin:0}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
body{
  background:var(--bg);color:var(--fg);
  font-family:var(--f-body);font-size:16px;line-height:1.65;font-weight:400;
  -webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;
  text-rendering:optimizeLegibility;font-variant-ligatures:none;
  min-height:100vh;overflow-x:hidden;
}
::selection{background:var(--sel);color:var(--sel-fg)}
img,svg{display:block;max-width:100%}
a{color:var(--accent-text);text-decoration:none}
a:hover{text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px}
/* Inline links inside running text must be distinguishable without colour (WCAG): underline them.
   Standalone link styles (.btn/.link-arrow/.related__link) keep their own affordance. */
p a:not(.btn):not(.link-arrow):not(.related__link),
li a:not(.btn):not(.link-arrow):not(.related__link),
dd a,td a,.faq__a a,.prose a,.consent p a,address a{
  text-decoration:underline;text-underline-offset:3px;text-decoration-thickness:1px}
:focus-visible{outline:2px solid var(--accent-text);outline-offset:3px}
button{font:inherit;color:inherit;background:none;border:none;cursor:pointer}
b,strong{font-weight:600}
hr{border:none;border-top:1px solid var(--line);margin:var(--s6) 0}

/* ---- Type --------------------------------------------------------------- */
h1,h2,h3,h4{font-family:var(--f-display);font-weight:700;line-height:1.08;letter-spacing:-0.015em;color:var(--fg)}
h3{font-size:1.3rem;font-weight:600;letter-spacing:-0.01em}
h4{font-size:1.05rem;font-weight:600;letter-spacing:0}
.mono{font-family:var(--f-mono);font-variant-numeric:tabular-nums}
.tnum{font-variant-numeric:tabular-nums}
.display-xl{font-size:clamp(2.6rem,6vw,4.6rem);line-height:1.0;letter-spacing:-0.02em}
.display-l{font-size:clamp(1.9rem,3.5vw,2.8rem);line-height:1.06;letter-spacing:-0.02em}
.lead{font-size:clamp(1.05rem,1.6vw,1.25rem);line-height:1.55;font-weight:500;color:var(--fg);max-width:60ch}
.muted{color:var(--muted)}
.accent{color:var(--accent-text)}
.small{font-size:.85rem}

/* eyebrow / kicker */
.eyebrow{font-family:var(--f-mono);font-size:.72rem;font-weight:500;text-transform:uppercase;
  letter-spacing:.14em;color:var(--muted);display:inline-flex;align-items:center;gap:.55em}
.eyebrow::before{content:"";width:14px;height:1px;background:var(--accent);flex:none}

/* section index numeral (drawing-sheet number) */
.index{font-family:var(--f-mono);font-size:.8rem;font-weight:500;color:var(--accent-text);letter-spacing:.06em}

/* ---- Layout primitives -------------------------------------------------- */
.wrap{max-width:var(--maxw);margin-inline:auto;padding-inline:var(--pad-inline)}
.section{padding-block:var(--sec)}
.section--tight{padding-block:clamp(40px,6vw,72px)}
.section + .section{border-top:1px solid var(--line)}
.section-head{max-width:72ch;margin-bottom:var(--s7)}
.section-head .display-l{margin-top:var(--s3)}
.section-head .lead{margin-top:var(--s4)}
.stack>*+*{margin-top:var(--s4)}
.grid{display:grid;gap:var(--s5)}
.cols-2{grid-template-columns:repeat(2,1fr)}
.cols-3{grid-template-columns:repeat(3,1fr)}
.cols-4{grid-template-columns:repeat(4,1fr)}
@media (max-width:900px){.cols-2,.cols-3,.cols-4{grid-template-columns:1fr}}
@media (min-width:901px){.cols-3--wrap{grid-template-columns:repeat(auto-fit,minmax(240px,1fr))}}

/* felt technical grid (hero / cta only) */
.gridfield{position:relative;isolation:isolate}
.gridfield::before{content:"";position:absolute;inset:0;z-index:-1;pointer-events:none;opacity:var(--grid-op);
  background-image:
    repeating-linear-gradient(0deg,transparent 0 23px,var(--line) 23px 24px),
    repeating-linear-gradient(90deg,transparent 0 23px,var(--line) 23px 24px);
  -webkit-mask-image:linear-gradient(180deg,#000,transparent 92%);mask-image:linear-gradient(180deg,#000,transparent 92%)}

/* ---- Skip link ---------------------------------------------------------- */
.skip{position:absolute;left:var(--s4);top:-64px;z-index:200;background:var(--surface);
  border:1px solid var(--line);padding:.6em 1em;font-family:var(--f-mono);font-size:.8rem;transition:top .15s}
.skip:focus{top:var(--s4);text-decoration:none}

/* ---- Header ------------------------------------------------------------- */
.site-header{position:sticky;top:0;z-index:100;background:color-mix(in srgb,var(--bg) 88%,transparent);
  backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.site-header__in{display:flex;align-items:center;gap:var(--s5);height:64px}
.wordmark{font-family:var(--f-display);font-weight:700;font-size:1.35rem;letter-spacing:.02em;color:var(--fg);
  display:inline-flex;align-items:baseline;gap:.5em}
.wordmark:hover{text-decoration:none}
.wordmark small{font-family:var(--f-mono);font-size:.6rem;font-weight:500;text-transform:uppercase;
  letter-spacing:.16em;color:var(--muted)}
.nav{margin-left:auto;display:flex;align-items:center;gap:clamp(12px,2vw,26px)}
.nav a{font-family:var(--f-mono);font-size:.8rem;letter-spacing:.02em;color:var(--muted)}
.nav a:hover,.nav a[aria-current="page"]{color:var(--fg);text-decoration:none}
.nav a[aria-current="page"]{position:relative}
.nav a[aria-current="page"]::after{content:"";position:absolute;left:0;right:0;bottom:-6px;height:1px;background:var(--accent)}
.icon-btn{width:36px;height:36px;display:inline-grid;place-items:center;border:1px solid var(--line);color:var(--muted)}
.icon-btn:hover{color:var(--fg);border-color:var(--muted)}
.nav-toggle{display:none}
@media (max-width:820px){
  .nav{position:fixed;inset:64px 0 auto 0;flex-direction:column;align-items:stretch;gap:0;background:var(--bg);
    border-bottom:1px solid var(--line);padding:var(--s3) var(--pad-inline) var(--s5);margin:0;
    transform:translateY(-12px);opacity:0;visibility:hidden;transition:.18s}
  .site-header[data-open="true"] .nav{transform:none;opacity:1;visibility:visible}
  .nav a{padding:var(--s4) 0;border-bottom:1px solid var(--line);font-size:.95rem}
  .nav .icon-btn{margin-top:var(--s4);width:auto;justify-self:start;padding-inline:var(--s4);gap:.5em}
  .nav-toggle{display:inline-grid;margin-left:auto}
}

/* ---- Titleblock hero ---------------------------------------------------- */
.titleblock{border:1px solid var(--line)}
.titleblock__fields{display:flex;flex-wrap:wrap;border-bottom:1px solid var(--line)}
.field{padding:.7em 1em;border-right:1px solid var(--line);font-family:var(--f-mono);font-size:.7rem;
  letter-spacing:.04em;flex:1 1 auto;min-width:max-content}
.field:last-child{border-right:none}
.field b{display:block;color:var(--muted);font-weight:500;text-transform:uppercase;font-size:.62rem;letter-spacing:.12em;margin-bottom:.35em}
.field span{color:var(--fg)}
.titleblock__body{padding:clamp(24px,5vw,56px)}
.titleblock__body .display-xl{margin:.1em 0 0}
.titleblock__body .lead{margin-top:var(--s5)}
.hero-lines{margin-top:var(--s5);display:flex;flex-direction:column;gap:.4em}
.hero-lines .mono{font-size:.82rem;color:var(--muted)}
.hero-lines .mono b{color:var(--fg)}
.hero-cta{margin-top:var(--s6);display:flex;flex-wrap:wrap;gap:var(--s4);align-items:center}

/* ---- Buttons ------------------------------------------------------------ */
.btn{display:inline-flex;align-items:center;gap:.6em;font-family:var(--f-mono);font-size:.82rem;
  letter-spacing:.03em;padding:.85em 1.4em;border:1px solid var(--fg);color:var(--fg);transition:.14s}
.btn:hover{text-decoration:none;background:var(--fg);color:var(--bg)}
.btn--accent{border-color:var(--accent);color:var(--accent-text)}
.btn--accent:hover{background:var(--accent);color:#fff}
.btn__arrow{transition:transform .14s}
.btn:hover .btn__arrow{transform:translateX(3px)}
.link-arrow{font-family:var(--f-mono);font-size:.8rem;letter-spacing:.02em;display:inline-flex;gap:.5em;align-items:center}
.link-arrow:hover{text-decoration:none}
.link-arrow span{transition:transform .14s}
.link-arrow:hover span{transform:translateX(3px)}

/* ---- Spec cards (signature) --------------------------------------------- */
.spec-card{border:1px solid var(--line);padding:clamp(20px,3vw,32px);background:var(--surface);
  display:flex;flex-direction:column;gap:var(--s4);position:relative;transition:border-color .14s}
.spec-card::before{content:"";position:absolute;left:-1px;top:-1px;width:0;height:34px;background:var(--accent);transition:width .14s}
.spec-card:hover{border-color:var(--muted)}
.spec-card:hover::before{width:3px}
.spec-card__head{display:flex;align-items:baseline;gap:var(--s4)}
.spec-card__head .index{font-size:1rem}
.spec-card h3{margin:0}
.spec-card__lead{color:var(--muted);font-size:.95rem}
.spec-card__foot{margin-top:auto;padding-top:var(--s4);border-top:1px solid var(--line)}

/* ---- Service hero (pillars + spokes) ------------------------------------ */
.svc-hero{display:grid;grid-template-columns:1.5fr 1fr;gap:clamp(32px,5vw,64px);align-items:start;margin-top:var(--s6)}
.svc-hero__main h1{margin-top:var(--s3)}
.svc-hero__main .lead{margin-top:var(--s4)}
.svc-hero__main .note{margin-top:var(--s5)}
.svc-hero__spec{border:1px solid var(--line);background:var(--surface);padding:var(--s5)}
@media (max-width:900px){.svc-hero{grid-template-columns:1fr;gap:var(--s6)}}

/* ---- Related links ------------------------------------------------------ */
.related{display:flex;flex-wrap:wrap;gap:0;border-top:1px solid var(--line)}
.related__link{flex:1 1 260px;padding:var(--s5) var(--s5) var(--s5) 0;border-bottom:1px solid var(--line);
  font-family:var(--f-mono);font-size:.82rem;color:var(--fg);display:flex;justify-content:space-between;gap:var(--s4);align-items:center}
.related__link span{color:var(--accent-text);transition:transform .14s}
.related__link:hover{text-decoration:none;color:var(--accent-text)}
.related__link:hover span{transform:translateX(3px)}

/* ---- Spec table (key:value) --------------------------------------------- */
.spec-table{width:100%;border-collapse:collapse;font-size:.85rem}
.spec-table th,.spec-table td{text-align:left;padding:.62em 0;border-bottom:1px solid var(--line);vertical-align:top}
.spec-table tr:last-child th,.spec-table tr:last-child td{border-bottom:none}
.spec-table th{font-family:var(--f-mono);font-weight:500;text-transform:uppercase;font-size:.68rem;
  letter-spacing:.1em;color:var(--muted);width:40%;white-space:nowrap;padding-right:var(--s4)}
.spec-table td{color:var(--fg);font-variant-numeric:tabular-nums}

/* ---- Deliverables / pillar lists ---------------------------------------- */
.deliverables{list-style:none;padding:0;display:grid;gap:0}
.deliverables li{padding:.85em 0 .85em 1.6em;border-bottom:1px solid var(--line);position:relative;font-size:.95rem}
.deliverables li:last-child{border-bottom:none}
.deliverables li::before{content:"";position:absolute;left:0;top:1.35em;width:8px;height:8px;border:1px solid var(--accent);background:transparent}
.deliverables li strong{font-weight:600}

.pillar-list{list-style:none;padding:0}
.pillar-list li{padding:var(--s5) 0;border-bottom:1px solid var(--line);display:grid;grid-template-columns:auto 1fr;gap:var(--s5)}
.pillar-list li:first-child{border-top:1px solid var(--line)}
.pillar-list .index{padding-top:.2em}
.pillar-list h4{margin:0 0 .4em}
.pillar-list p{color:var(--muted);font-size:.95rem;margin:0}

/* ---- FAQ ---------------------------------------------------------------- */
.faq{border-top:1px solid var(--line)}
.faq details{border-bottom:1px solid var(--line)}
.faq summary{list-style:none;cursor:pointer;padding:var(--s5) 2.4em var(--s5) 0;position:relative;
  font-family:var(--f-display);font-weight:600;font-size:1.05rem;letter-spacing:-0.01em;color:var(--fg)}
.faq summary::-webkit-details-marker{display:none}
.faq summary::after{content:"+";position:absolute;right:0;top:50%;transform:translateY(-50%);
  font-family:var(--f-mono);color:var(--accent-text);font-size:1.3rem;line-height:1}
.faq details[open] summary::after{content:"\2013"}
.faq summary:hover{color:var(--accent-text)}
.faq__a{padding:0 0 var(--s5);color:var(--muted);max-width:var(--measure)}
.faq__a p+p{margin-top:var(--s3)}

/* ---- CTA band ----------------------------------------------------------- */
.cta{border:1px solid var(--line);background:var(--surface);padding:clamp(32px,6vw,72px);text-align:left}
.cta h2{max-width:20ch}
.cta .lead{margin-top:var(--s4)}
.cta .hero-cta{margin-top:var(--s6)}

/* ---- Breadcrumb --------------------------------------------------------- */
.breadcrumb{padding-top:var(--s6);font-family:var(--f-mono);font-size:.74rem;letter-spacing:.04em;color:var(--muted)}
.breadcrumb ol{list-style:none;padding:0;display:flex;flex-wrap:wrap;gap:.5em;align-items:center}
.breadcrumb li{display:flex;gap:.5em;align-items:center}
.breadcrumb li+li::before{content:"/";color:var(--line)}
.breadcrumb a{color:var(--muted)}
.breadcrumb a:hover{color:var(--fg)}
.breadcrumb [aria-current="page"]{color:var(--fg)}

/* ---- Signal line motif & dimension line --------------------------------- */
.signal svg{width:100%;height:auto;color:var(--accent)}
.dimension{display:inline-flex;align-items:center;gap:.7em;font-family:var(--f-mono);font-size:.72rem;
  letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.dimension b{font-family:var(--f-display);font-size:1.5rem;letter-spacing:-0.02em;color:var(--fg);text-transform:none}
.dimension::before,.dimension::after{content:"";height:1px;width:18px;background:var(--accent)}

/* ---- Note / scope callout ----------------------------------------------- */
.note{border-left:2px solid var(--accent);padding:.4em 0 .4em 1.2em;color:var(--muted);font-size:.92rem}
.note b{color:var(--fg);font-weight:600}
.tag{display:inline-block;font-family:var(--f-mono);font-size:.66rem;text-transform:uppercase;letter-spacing:.12em;
  color:var(--muted);border:1px solid var(--line);padding:.3em .6em}

/* ---- Prose (insights) --------------------------------------------------- */
.prose{max-width:var(--measure)}
.prose>*+*{margin-top:var(--s5)}
.prose h2{font-size:clamp(1.5rem,2.4vw,2rem);margin-top:var(--s8);letter-spacing:-0.02em}
.prose h3{margin-top:var(--s6)}
.prose p,.prose li{color:var(--fg);opacity:.92}
.prose ul,.prose ol{padding-left:1.3em}
.prose li+li{margin-top:.4em}
.prose a{color:var(--accent-text);text-decoration:underline;text-underline-offset:3px}
.prose blockquote{border-left:2px solid var(--accent);padding-left:1.2em;color:var(--muted);font-style:italic}
.prose code{font-family:var(--f-mono);font-size:.85em;background:var(--surface);border:1px solid var(--line);padding:.1em .4em}
.prose figcaption,.figcap{font-family:var(--f-mono);font-size:.72rem;color:var(--muted);margin-top:.6em}
.article-meta{font-family:var(--f-mono);font-size:.74rem;letter-spacing:.04em;color:var(--muted);
  display:flex;flex-wrap:wrap;gap:var(--s4);padding-top:var(--s4)}

/* article/insight list */
.entry{display:grid;grid-template-columns:auto 1fr;gap:var(--s5);padding:var(--s6) 0;border-bottom:1px solid var(--line)}
.entry:first-child{border-top:1px solid var(--line)}
.entry__date{font-family:var(--f-mono);font-size:.74rem;color:var(--muted);white-space:nowrap;padding-top:.3em}
.entry h3{margin:0 0 .4em}
.entry p{color:var(--muted);font-size:.95rem;margin:0}
@media (max-width:640px){.entry{grid-template-columns:1fr;gap:var(--s2)}}

/* ---- Footer ------------------------------------------------------------- */
.site-footer{border-top:1px solid var(--line);margin-top:var(--sec);padding-block:var(--s8) var(--s6)}
.site-footer__grid{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:var(--s7)}
@media (max-width:760px){.site-footer__grid{grid-template-columns:1fr 1fr}}
@media (max-width:460px){.site-footer__grid{grid-template-columns:1fr}}
.footer-brand .wordmark{font-size:1.6rem}
.footer-brand p{color:var(--muted);font-size:.85rem;margin-top:var(--s4);max-width:34ch}
.footer-col h4{font-family:var(--f-mono);font-size:.68rem;text-transform:uppercase;letter-spacing:.12em;
  color:var(--muted);font-weight:500;margin-bottom:var(--s4)}
.footer-col ul{list-style:none;padding:0;display:grid;gap:.6em}
.footer-col a{color:var(--fg);font-size:.9rem}
.footer-col a:hover{color:var(--accent-text)}
.footer-meta{display:flex;flex-wrap:wrap;gap:var(--s3) var(--s5);align-items:center;justify-content:space-between;
  margin-top:var(--s8);padding-top:var(--s5);border-top:1px solid var(--line);
  font-family:var(--f-mono);font-size:.72rem;letter-spacing:.03em;color:var(--muted)}
.footer-meta a{color:var(--muted)}
.footer-addr{font-style:normal}

/* ---- Consent banner ----------------------------------------------------- */
.consent{position:fixed;inset:auto var(--s4) var(--s4) var(--s4);z-index:150;max-width:520px;margin-inline:auto;
  background:var(--surface);border:1px solid var(--line);padding:var(--s5);display:none}
.consent[data-show="true"]{display:block}
.consent p{font-size:.85rem;color:var(--muted)}
.consent p b{color:var(--fg)}
.consent__row{display:flex;gap:var(--s3);margin-top:var(--s4);flex-wrap:wrap}
.consent .btn{padding:.6em 1.1em;font-size:.76rem}

/* ---- Utilities ---------------------------------------------------------- */
.visually-hidden{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.center{text-align:center}
.mt-0{margin-top:0}
.maxw-prose{max-width:var(--measure)}
@media (prefers-reduced-motion:reduce){*{animation-duration:.001ms!important;transition-duration:.001ms!important}}