/* ============================================================
   SUBSTRATE — the inference layer for production AI
   Style register: "Jensen Huang" — precise, contained, function
   over form, one restrained accent. Enterprise/investor-facing.
   Demo build for the Stack Studios portfolio.
   ============================================================ */

:root {
  /* cool engineering palette */
  --bg:        #F6F7F9;
  --surface:   #FFFFFF;
  --surface-2: #EDF0F4;
  --ink:       #0D1017;
  --ink-soft:  #384150;
  --muted:     #6A7686;
  --hairline:  #E3E7ED;
  --hairline-2:#EEF1F5;
  --accent:    #4F46E5;   /* electric indigo — CTAs, key metrics, links ONLY */
  --accent-2:  #6366F1;
  --sig:      var(--accent);                                  /* Stack Studios signature — the demo's own accent */
  --sig-line: color-mix(in srgb, var(--sig) 55%, transparent);
  --accent-soft:#ECEDFB;
  --ok:        #16A34A;

  --sans: "IBM Plex Sans", system-ui, -apple-system, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SF Mono", monospace;

  --maxw: 1160px;
  --gutter: clamp(20px, 4vw, 40px);
  --section: clamp(72px, 9vw, 128px);
  --r: 12px;
  --r-sm: 8px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

*,*::before,*::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: var(--sans); font-size: 16px; line-height: 1.6; font-weight: 400;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}
img,svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; }
h1,h2,h3,h4 { margin: 0; font-weight: 600; letter-spacing: -0.02em; line-height: 1.1; }
p { margin: 0; }
::selection { background: var(--accent); color: #fff; }

/* layout */
.wrap { max-width: var(--maxw); margin-inline: auto; padding-inline: var(--gutter); }
.section { padding-block: var(--section); }
.section-tight { padding-block: clamp(48px,6vw,80px); }
.sr-only { position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0; }
.skip-link { position:absolute;left:-999px;top:8px;z-index:200;background:var(--ink);color:#fff;padding:10px 16px;border-radius:6px; }
.skip-link:focus { left:8px; }

/* type scale */
.eyebrow { font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent); font-weight: 500; }
.h-xl { font-size: clamp(2.4rem, 5.2vw, 4.1rem); letter-spacing: -0.035em; }
.h-l  { font-size: clamp(1.9rem, 3.6vw, 3rem); letter-spacing: -0.03em; }
.h-m  { font-size: clamp(1.3rem, 2.2vw, 1.8rem); }
.lede { font-size: clamp(1.05rem, 1.5vw, 1.25rem); color: var(--ink-soft); line-height: 1.55; max-width: 52ch; }
.muted { color: var(--muted); }
.measure { max-width: 60ch; }

/* focus */
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }

/* nav */
.nav { position: sticky; top: 0; z-index: 100; background: rgba(246,247,249,.85); backdrop-filter: saturate(160%) blur(12px); -webkit-backdrop-filter: saturate(160%) blur(12px); border-bottom: 1px solid var(--hairline); }
.nav-in { display: flex; align-items: center; justify-content: space-between; height: 62px; }
.brand { display: inline-flex; align-items: center; gap: 9px; font-weight: 600; font-size: 1.08rem; letter-spacing: -0.01em; color: var(--ink); }
.nav-links { display: flex; align-items: center; gap: clamp(18px,2.4vw,34px); list-style: none; margin: 0; padding: 0; }
.nav-links a { font-size: 0.92rem; color: var(--ink-soft); transition: color .18s; }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--ink); }
.nav-actions { display: flex; align-items: center; gap: 14px; }
.nav-toggle { display: none; background: none; border: 0; padding: 8px; }
.nav-toggle span { display:block;width:22px;height:1.5px;background:var(--ink);margin:5px 0; }

/* buttons */
.btn { display:inline-flex;align-items:center;gap:8px;font-family:var(--sans);font-size:0.94rem;font-weight:500;padding:11px 20px;border-radius:8px;border:1px solid transparent;transition:background .18s,color .18s,border-color .18s,transform .12s; white-space: nowrap; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #4038d6; }
.btn:active, .btn-primary:active, .nav-toggle:active { transform: scale(.97); }
.btn-ghost { background: var(--surface); color: var(--ink); border-color: var(--hairline); }
.btn-ghost:hover { border-color: var(--ink-soft); }
.btn-sm { padding: 8px 14px; font-size: 0.88rem; }
.btn .arw { transition: transform .2s var(--ease); }
.btn:hover .arw { transform: translateX(3px); }

/* hero */
.hero { padding-top: clamp(48px,7vw,88px); padding-bottom: var(--section); }
.hero-grid { display: grid; grid-template-columns: 1.05fr 0.95fr; gap: clamp(32px,5vw,64px); align-items: center; }
.hero h1 { margin-top: 18px; }
.hero .lede { margin-top: 20px; }
.hero-cta { margin-top: 28px; display: flex; gap: 12px; flex-wrap: wrap; align-items: center; }
.hero-note { margin-top: 16px; font-family: var(--mono); font-size: 0.78rem; color: var(--muted); }

/* the inference console — the product, built in CSS */
.console { background: var(--ink); border-radius: var(--r); overflow: hidden; box-shadow: 0 30px 60px -24px rgba(13,16,23,.5); border: 1px solid #1b2130; }
.console-bar { display:flex;align-items:center;gap:8px;padding:12px 16px;border-bottom:1px solid #1b2130; }
.console-bar .k { font-family: var(--mono); font-size: 0.72rem; color: #8b95a7; letter-spacing: .04em; }
.console-bar .live { margin-left:auto;display:inline-flex;align-items:center;gap:6px;font-family:var(--mono);font-size:0.68rem;color:#9aa4b6; }
.live-dot { width:7px;height:7px;border-radius:50%;background:var(--ok);box-shadow:0 0 0 0 rgba(22,163,74,.5); }
.console-body { padding: 18px 16px 20px; display: grid; gap: 14px; }
.metric-row { display: grid; grid-template-columns: 1fr auto; align-items: baseline; gap: 12px; }
.metric-row .lbl { font-family: var(--mono); font-size: 0.74rem; color: #8b95a7; }
.metric-row .val { font-family: var(--mono); font-size: 1.15rem; color: #fff; font-weight: 500; font-variant-numeric: tabular-nums; }
.metric-row .val b { color: var(--accent-2); font-weight: 600; }
.spark { height: 46px; display:flex; align-items:flex-end; gap:3px; padding-top:4px; }
.spark span { flex:1; background: linear-gradient(180deg, var(--accent-2), #2a2f6b); border-radius: 2px 2px 0 0; opacity:.85; }
.console-foot { border-top:1px solid #1b2130; padding:11px 16px; display:flex;justify-content:space-between;font-family:var(--mono);font-size:0.7rem;color:#6f7a8d; }

/* logo trust row */
.trust { display:flex;align-items:center;justify-content:center;gap:clamp(24px,5vw,56px);flex-wrap:wrap;opacity:.72; }
.trust .logo { font-weight:600;font-size:1.05rem;letter-spacing:-0.02em;color:var(--ink-soft);display:inline-flex;align-items:center;gap:7px; }
.trust .logo .m { width:15px;height:15px;border-radius:4px;background:var(--ink-soft); }
.trust-label { text-align:center;font-family:var(--mono);font-size:0.72rem;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin-bottom:26px; }

/* section header */
.sec-head { max-width: 640px; }
.sec-head.center { margin-inline:auto; text-align:center; }
.sec-head .h-l { margin-top: 14px; }
.sec-head p { margin-top: 16px; }

/* feature cards — contained grid */
.grid-3 { display:grid;grid-template-columns:repeat(3,1fr);gap:20px; }
.grid-2 { display:grid;grid-template-columns:repeat(2,1fr);gap:20px; }
.card { background: var(--surface); border: 1px solid var(--hairline); border-radius: var(--r); padding: 26px 24px; transition: border-color .2s, transform .2s var(--ease), box-shadow .2s; }
.card:hover { border-color: #cfd6e0; box-shadow: 0 12px 30px -18px rgba(13,16,23,.18); }
.card .ic { width:38px;height:38px;border-radius:9px;background:var(--accent-soft);display:grid;place-items:center;margin-bottom:16px; }
.card .ic svg { width:19px;height:19px;stroke:var(--accent); }
.card h3 { font-size: 1.1rem; margin-bottom: 8px; }
.card p { font-size: 0.92rem; color: var(--muted); line-height: 1.6; }
.card .kv { font-family: var(--mono); font-size: 0.72rem; color: var(--accent); letter-spacing:.06em; margin-bottom: 12px; }

/* dark stat band */
.band-dark { background: var(--ink); color: #fff; border-radius: var(--r); padding: clamp(36px,5vw,60px); }
.stat-grid { display:grid;grid-template-columns:repeat(4,1fr);gap:28px; }
.stat .n { font-size: clamp(2.1rem,4vw,3.1rem); font-weight: 600; letter-spacing:-0.03em; font-variant-numeric: tabular-nums; }
.stat .n small { font-size:0.42em;font-weight:500;color:var(--accent-2);margin-left:2px; }
.stat .k { font-family: var(--mono); font-size: 0.74rem; color: #9aa4b6; margin-top: 8px; letter-spacing:.03em; }

/* media */
.media { border-radius: var(--r); overflow: hidden; border: 1px solid var(--hairline); background: var(--surface-2); }
.media img { width:100%;height:100%;object-fit:cover;display:block; }
.split { display:grid;grid-template-columns:1fr 1fr;gap:clamp(28px,4vw,56px);align-items:center; }
.split.rev .split-media { order:-1; }

/* code / spec block */
.code { background: var(--ink); border-radius: var(--r); overflow: hidden; border:1px solid #1b2130; }
.code-bar { padding:11px 16px; border-bottom:1px solid #1b2130; font-family:var(--mono); font-size:0.72rem; color:#8b95a7; }
.code pre { margin:0; padding:20px 18px; overflow-x:auto; font-family:var(--mono); font-size:0.82rem; line-height:1.7; color:#c8cfda; }
.code .cm { color:#6f7a8d; } .code .kw { color:var(--accent-2); } .code .st { color:#7fd1a6; }

/* spec table */
.spec-table { width:100%; border-collapse:collapse; }
.spec-table tr { border-top:1px solid var(--hairline); }
.spec-table tr:last-child { border-bottom:1px solid var(--hairline); }
.spec-table th,.spec-table td { text-align:left; padding:16px 0; vertical-align:top; font-weight:400; }
.spec-table th { width:32%; color:var(--muted); font-family:var(--mono); font-size:0.76rem; letter-spacing:.06em; text-transform:uppercase; }
.spec-table td { font-size:0.98rem; }

/* portrait */
.portrait { border-radius: var(--r); overflow:hidden; border:1px solid var(--hairline); aspect-ratio:3/4; background:var(--surface-2); }
.portrait img { width:100%;height:100%;object-fit:cover; }

/* CTA */
.cta { background: var(--ink); border-radius: var(--r); padding: clamp(40px,6vw,72px); text-align:center; color:#fff; }
.cta h2 { color:#fff; } .cta p { color:#aeb6c4; margin:14px auto 0; }
.cta .hero-cta { justify-content:center; margin-top:26px; }
.cta .btn-ghost { background:transparent; color:#fff; border-color:#2a3040; }
.cta .btn-ghost:hover { border-color:#556074; }

/* forms (contact) */
.field { display:grid; gap:7px; margin-bottom:18px; }
.field label { font-size:0.84rem; font-weight:500; color:var(--ink-soft); }
.field input,.field textarea,.field select { font:inherit; padding:11px 13px; border:1px solid var(--hairline); border-radius:var(--r-sm); background:var(--surface); color:var(--ink); }
.field input:focus,.field textarea:focus,.field select:focus { outline:2px solid var(--accent); outline-offset:0; border-color:transparent; }

/* footer */
.footer { border-top:1px solid var(--hairline); padding-block: clamp(48px,6vw,72px) 36px; }
.footer-grid { display:grid; grid-template-columns:1.5fr 1fr 1fr 1fr; gap:32px; }
.footer h4 { font-family:var(--mono); font-size:0.72rem; letter-spacing:.1em; text-transform:uppercase; color:var(--muted); font-weight:500; margin-bottom:14px; }
.footer nav a { display:block; padding:5px 0; color:var(--ink-soft); font-size:0.9rem; }
.footer nav a:hover { color:var(--ink); }
.footer-bot { display:flex; justify-content:space-between; align-items:center; margin-top:40px; padding-top:22px; border-top:1px solid var(--hairline); flex-wrap:wrap; gap:10px; font-size:0.8rem; color:var(--muted); }
.demo-flag { font-family:var(--mono); font-size:0.68rem; letter-spacing:.1em; text-transform:uppercase; color:var(--muted); border:1px solid var(--hairline); border-radius:100px; padding:5px 12px; }

/* page hero / crumbs */
.page-hero { padding-top: clamp(48px,6vw,80px); }
.crumbs { font-family:var(--mono); font-size:0.74rem; letter-spacing:.06em; color:var(--muted); text-transform:uppercase; margin-bottom:18px; }
.crumbs a:hover { color:var(--ink); }

.rule { border:0; border-top:1px solid var(--hairline); margin:0; }
.pill { display:inline-block; font-family:var(--mono); font-size:0.72rem; color:var(--accent); background:var(--accent-soft); padding:5px 11px; border-radius:100px; letter-spacing:.03em; }

/* ============================================================
   STACK STUDIOS SIGNATURE — recurring craft, in this demo's own
   accent (--sig). Seam hairline · one orchestrated first-load
   moment · footer mark · press feedback. Style-agnostic by design.
   ============================================================ */
.sig-kicker { display:inline-flex; align-items:center; gap:14px; }
.sig-seam   { display:inline-block; width:34px; height:1px; background:var(--sig); transform-origin:left center; flex:none; }
.sig-mask   { display:block; overflow:hidden; padding-block:.12em; margin-block:-.12em; }
.sig-rule   { display:flex; align-items:center; gap:16px; }
.sig-rule::after { content:""; flex:1; height:1px; background:var(--sig-line); }
.sig-credit  { display:inline-flex; align-items:center; gap:9px; }
.sig-emblem  { width:15px; height:15px; color:var(--sig); flex:none; }

@media (prefers-reduced-motion: no-preference){
  /* First-load choreography — pure CSS, plays on load once the inline <head>
     bootstrap adds `.js` (synchronous, before first paint). No dependency on any
     script finishing; with JS off or reduced motion the rules simply don't apply
     and all content is fully visible. Seam draws → headline rises from its mask
     → hero items stagger up. */
  .js .sig-seam      { animation:sig-draw .70s var(--ease) .12s both; }
  .js .sig-mask > h1 { animation:sig-rise .85s var(--ease) .18s both; }
  .js .sig-hero      { animation:sig-up   .60s var(--ease) both; }
  .js .sig-d1 { animation-delay:.08s; }
  .js .sig-d2 { animation-delay:.30s; }
  .js .sig-d3 { animation-delay:.40s; }
  @keyframes sig-draw { from{transform:scaleX(0);}        to{transform:scaleX(1);} }
  @keyframes sig-rise { from{transform:translateY(118%);} to{transform:translateY(0);} }
  @keyframes sig-up   { from{opacity:0;transform:translateY(20px);} to{opacity:1;transform:none;} }
}

/* reveal */
@media (prefers-reduced-motion: no-preference) {
  .js .fade { opacity:0; transform:translateY(16px); transition:opacity .6s var(--ease), transform .6s var(--ease); }
  .js .fade.in { opacity:1; transform:none; }
  .live-dot { animation: pulse 2s infinite; }
  @keyframes pulse { 0%{box-shadow:0 0 0 0 rgba(22,163,74,.5)} 70%{box-shadow:0 0 0 6px rgba(22,163,74,0)} 100%{box-shadow:0 0 0 0 rgba(22,163,74,0)} }
}

/* responsive */
@media (max-width: 900px) {
  .hero-grid, .split, .grid-3, .grid-2, .footer-grid, .stat-grid { grid-template-columns: 1fr; }
  .grid-3, .grid-2 { gap:16px; }
  .stat-grid { grid-template-columns: 1fr 1fr; gap:24px; }
  .split.rev .split-media { order:0; }
  .footer-grid { grid-template-columns:1fr 1fr; }
  .nav-links, .nav-actions .btn-ghost { display:none; }
  .nav-toggle { display:block; }
  .nav-links.open { display:flex; position:fixed; inset:62px 0 auto 0; flex-direction:column; align-items:flex-start; gap:0; background:var(--bg); border-bottom:1px solid var(--hairline); padding:8px var(--gutter) 18px; }
  .nav-links.open li { width:100%; border-top:1px solid var(--hairline-2); }
  .nav-links.open a { display:block; padding:14px 0; font-size:1.02rem; }
}
@media (max-width:560px){ .stat-grid{grid-template-columns:1fr} .footer-grid{grid-template-columns:1fr} }