/* StretchAI — layout & components. Static, no framework. */

*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--ai-bg);
  color: var(--ai-body);
  font-family: var(--ai-font);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: inherit; text-decoration: none; }
img, svg { display: block; max-width: 100%; }

h1, h2, h3, h4 { color: var(--ai-ink); font-weight: 600; letter-spacing: var(--ai-tight); line-height: 1.08; margin: 0; }
p { margin: 0; }

::selection { background: var(--ai-accent-dim); color: var(--ai-ink); }

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

.wrap { width: 100%; max-width: var(--ai-maxw); margin: 0 auto; padding: 0 var(--ai-gutter); }

.muted { color: var(--ai-muted); }
.subtle { color: var(--ai-subtle); }
.mono { font-family: var(--ai-mono); font-size: 0.82em; letter-spacing: 0; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 10px 18px; border-radius: var(--ai-radius);
  font-size: 0.94rem; font-weight: 500; cursor: pointer;
  border: 1px solid transparent; transition: background .15s ease, border-color .15s ease, color .15s ease, transform .15s ease;
}
.btn:active { transform: translateY(1px); }
.btn--primary { background: var(--ai-cta); color: var(--ai-cta-ink); }
.btn--primary:hover { background: var(--ai-cta-hover); }
.btn--ghost { background: transparent; color: var(--ai-ink); border-color: var(--ai-border-strong); }
.btn--ghost:hover { border-color: var(--ai-border-hover); background: rgba(255,255,255,.03); }
.btn--sm { padding: 7px 13px; font-size: 0.86rem; }

/* ---------- Nav ---------- */
.nav {
  position: sticky; top: 0; z-index: 100;
  height: var(--ai-nav-h);
  background: rgba(10, 10, 11, 0.72);
  backdrop-filter: saturate(140%) blur(12px);
  border-bottom: 1px solid var(--ai-border);
}
.nav__inner { height: 100%; display: flex; align-items: center; gap: 28px; }
.nav__brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 600; color: var(--ai-ink); letter-spacing: -0.02em; font-size: 1.05rem; }
.nav__brand .logomark { height: 22px; width: auto; }
.nav__brand .brand-sub { color: var(--ai-subtle); font-weight: 400; font-size: 0.82rem; }

.nav__links { display: flex; align-items: center; gap: 4px; height: 100%; }
.nav__spacer { flex: 1; }
.nav__cta { display: flex; align-items: center; gap: 10px; }
.nav__cta-mobile { display: none; }

.nav__item { position: relative; height: 100%; display: flex; align-items: center; }
.nav__trigger {
  display: inline-flex; align-items: center; gap: 5px;
  height: 100%; padding: 0 12px;
  font-size: 0.92rem; color: var(--ai-body); background: none; border: none; cursor: pointer;
  font-family: inherit; transition: color .15s ease;
}
.nav__trigger:hover, .nav__item[data-open="true"] .nav__trigger { color: var(--ai-ink); }
.nav__trigger .caret { width: 11px; height: 11px; opacity: .55; transition: transform .18s ease; }
.nav__item[data-open="true"] .nav__trigger .caret { transform: rotate(180deg); }

.nav__toggle { display: none; }

/* ---------- Mega menu ---------- */
.mega {
  position: absolute; top: calc(var(--ai-nav-h) - 1px); left: 50%; transform: translateX(-50%) translateY(8px);
  width: min(920px, calc(100vw - 32px));
  background: var(--ai-panel); border: 1px solid var(--ai-border-strong);
  border-radius: var(--ai-radius-lg); box-shadow: var(--ai-shadow-menu);
  padding: 22px; opacity: 0; visibility: hidden; pointer-events: none;
  transition: opacity .16s ease, transform .16s ease, visibility .16s;
}
.nav__item[data-open="true"] .mega { opacity: 1; visibility: visible; pointer-events: auto; transform: translateX(-50%) translateY(0); }
.mega--narrow { width: min(640px, calc(100vw - 32px)); }

.mega__grid { display: grid; grid-template-columns: repeat(var(--cols, 4), 1fr); gap: 10px 22px; }
.mega__col h4 { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.09em; color: var(--ai-subtle); margin-bottom: 10px; font-weight: 600; }
.mega__link { display: block; padding: 9px 10px; border-radius: 8px; color: var(--ai-body); transition: background .12s ease, color .12s ease; }
.mega__link:hover { background: var(--ai-panel-alt); color: var(--ai-ink); }
.mega__link strong { display: block; color: var(--ai-ink); font-weight: 500; font-size: 0.92rem; }
.mega__link span { display: block; font-size: 0.8rem; color: var(--ai-muted); margin-top: 1px; }

.mega__feature {
  grid-row: span 5; align-self: stretch;
  background: linear-gradient(160deg, var(--ai-panel-alt), var(--ai-panel));
  border: 1px solid var(--ai-border); border-radius: var(--ai-radius);
  padding: 16px; display: flex; flex-direction: column; gap: 8px;
}
.mega__feature .eyebrow { font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--ai-accent); }
.mega__feature strong { color: var(--ai-ink); font-size: 1rem; }
.mega__feature p { font-size: 0.82rem; color: var(--ai-muted); }
.mega__feature .spacer { flex: 1; }

/* ---------- Status chips ---------- */
.chip {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 3px 10px; border-radius: var(--ai-chip-radius);
  font-size: 0.72rem; font-weight: 600; letter-spacing: 0.01em;
  white-space: nowrap;
}
.chip::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: currentColor; opacity: .9; }
.chip--live    { background: var(--ai-live-bg);     color: var(--ai-live-ink); }
.chip--trained { background: var(--ai-trained-bg);  color: var(--ai-trained-ink); }
.chip--planned { background: var(--ai-planned-bg);  color: var(--ai-planned-ink); }
.chip--governed{ background: var(--ai-governed-bg); color: var(--ai-governed-ink); }
.chip--bare::before { display: none; }

/* ---------- Sections ---------- */
.section { padding: 84px 0; border-top: 1px solid var(--ai-border); }
.section--flush { border-top: none; }
.section--surface { background: var(--ai-surface); }
.section__head { max-width: 680px; margin-bottom: 40px; }
.eyebrow { display: inline-block; font-size: 0.74rem; text-transform: uppercase; letter-spacing: 0.12em; color: var(--ai-accent); margin-bottom: 14px; font-weight: 600; }
.section h2 { font-size: var(--ai-h2); }
.section__head p { margin-top: 14px; font-size: var(--ai-lede); color: var(--ai-muted); }

/* ---------- Hero ---------- */
.hero { padding: clamp(72px, 12vh, 140px) 0 84px; position: relative; overflow: hidden; }
.hero::after {
  content: ""; position: absolute; inset: 0; z-index: -1;
  background:
    radial-gradient(60% 50% at 70% 0%, rgba(110, 231, 210, 0.06), transparent 70%),
    radial-gradient(50% 40% at 10% 20%, rgba(155, 220, 255, 0.05), transparent 70%);
}
.hero h1 { font-size: var(--ai-h1); max-width: 16ch; }
.hero .lede { margin-top: 22px; max-width: 56ch; font-size: var(--ai-lede); color: var(--ai-muted); }
.hero__actions { margin-top: 34px; display: flex; gap: 12px; flex-wrap: wrap; }
.hero__meta { margin-top: 46px; display: flex; gap: 32px; flex-wrap: wrap; color: var(--ai-muted); font-size: 0.86rem; }
.hero__meta b { color: var(--ai-ink); font-weight: 600; display: block; font-size: 1.5rem; letter-spacing: -0.02em; }

/* ---------- Featured model band ---------- */
.feature { display: grid; grid-template-columns: 1.05fr 0.95fr; gap: 48px; align-items: center; }
.feature__spec {
  background: var(--ai-panel); border: 1px solid var(--ai-border); border-radius: var(--ai-radius-lg);
  padding: 26px; display: grid; grid-template-columns: 1fr 1fr; gap: 18px 22px;
}
.feature__spec .cell .k { font-size: 0.74rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--ai-subtle); }
.feature__spec .cell .v { color: var(--ai-ink); font-weight: 600; margin-top: 4px; font-size: 1.05rem; }
.feature__spec .cell .v small { display: block; font-weight: 400; color: var(--ai-muted); font-size: 0.78rem; margin-top: 2px; }
.feature h2 { font-size: var(--ai-h2); margin-bottom: 10px; }
.feature .lede { color: var(--ai-muted); font-size: var(--ai-lede); margin: 16px 0 22px; }

/* ---------- Model catalog grid ---------- */
.filters { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 26px; }
.filter {
  padding: 6px 14px; border-radius: var(--ai-chip-radius); font-size: 0.84rem;
  background: var(--ai-panel); border: 1px solid var(--ai-border); color: var(--ai-muted);
  cursor: pointer; font-family: inherit; transition: all .14s ease;
}
.filter:hover { color: var(--ai-ink); border-color: var(--ai-border-strong); }
.filter[aria-pressed="true"] { background: var(--ai-ink); color: var(--ai-bg); border-color: var(--ai-ink); }

.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 14px; }
.card {
  background: var(--ai-panel); border: 1px solid var(--ai-border); border-radius: var(--ai-radius);
  padding: 18px; display: flex; flex-direction: column; gap: 8px;
  transition: border-color .15s ease, transform .15s ease, background .15s ease;
}
.card:hover { border-color: var(--ai-border-hover); transform: translateY(-2px); }
.card__top { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.card__name { color: var(--ai-ink); font-weight: 600; font-size: 1.02rem; }
.card__id { color: var(--ai-subtle); margin-top: 1px; }
.card__desc { color: var(--ai-muted); font-size: 0.88rem; }
.card__cat { margin-top: auto; padding-top: 6px; font-size: 0.74rem; color: var(--ai-subtle); text-transform: uppercase; letter-spacing: 0.07em; }

/* ---------- Stat band ---------- */
.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 1px; background: var(--ai-border); border: 1px solid var(--ai-border); border-radius: var(--ai-radius-lg); overflow: hidden; }
.stats .stat { background: var(--ai-panel); padding: 26px 22px; }
.stats .stat b { display: block; color: var(--ai-ink); font-size: 2.2rem; font-weight: 600; letter-spacing: -0.03em; }
.stats .stat span { color: var(--ai-muted); font-size: 0.88rem; margin-top: 4px; display: block; }

/* ---------- Feature list (cognitive / research) ---------- */
.tiles { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 14px; }
.tile { background: var(--ai-panel); border: 1px solid var(--ai-border); border-radius: var(--ai-radius); padding: 22px; }
.tile h3 { font-size: var(--ai-h3); margin-bottom: 8px; }
.tile p { color: var(--ai-muted); font-size: 0.9rem; }
.tile .num { font-family: var(--ai-mono); font-size: 0.78rem; color: var(--ai-accent); margin-bottom: 10px; }

/* ---------- Roadmap ladder ---------- */
.ladder { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 36px; }
.rung { flex: 1; min-width: 130px; background: var(--ai-panel); border: 1px solid var(--ai-border); border-radius: var(--ai-radius); padding: 16px; }
.rung .step { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--ai-subtle); }
.rung .n { color: var(--ai-ink); font-size: 1.6rem; font-weight: 600; letter-spacing: -0.02em; margin-top: 6px; }
.rung--active { border-color: var(--ai-accent); }
.rung--active .step { color: var(--ai-accent); }

/* ---------- CTA band ---------- */
.cta-band { text-align: center; padding: 96px 0; border-top: 1px solid var(--ai-border); background: var(--ai-surface); }
.cta-band h2 { font-size: var(--ai-h2); max-width: 22ch; margin: 0 auto 12px; }
.cta-band p { color: var(--ai-muted); max-width: 48ch; margin: 0 auto 28px; font-size: var(--ai-lede); }

/* ---------- Footer ---------- */
.footer { border-top: 1px solid var(--ai-border); padding: 56px 0 40px; background: var(--ai-bg); }
.footer__grid { display: grid; grid-template-columns: 1.6fr repeat(4, 1fr); gap: 32px; }
.footer__brand .logomark { height: 20px; margin-bottom: 14px; }
.footer__brand p { color: var(--ai-muted); font-size: 0.86rem; max-width: 30ch; }
.footer__col h5 { color: var(--ai-ink); font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 14px; font-weight: 600; }
.footer__col a { display: block; color: var(--ai-muted); font-size: 0.88rem; padding: 5px 0; transition: color .12s ease; }
.footer__col a:hover { color: var(--ai-ink); }
.footer__bar { margin-top: 44px; padding-top: 22px; border-top: 1px solid var(--ai-border); display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; color: var(--ai-subtle); font-size: 0.82rem; }

/* ---------- Generic prose (sub-pages) ---------- */
.lead-block { max-width: 760px; }
.lead-block h1 { font-size: var(--ai-h1); margin-bottom: 18px; }
.lead-block .lede { font-size: var(--ai-lede); color: var(--ai-muted); }
.prose { max-width: 720px; }
.prose h2 { font-size: var(--ai-h2); margin: 44px 0 14px; }
.prose h3 { font-size: var(--ai-h3); margin: 28px 0 8px; }
.prose p { color: var(--ai-body); margin-bottom: 14px; }
.prose ul { color: var(--ai-body); padding-left: 20px; margin-bottom: 14px; }
.prose li { margin-bottom: 8px; }
.prose code { font-family: var(--ai-mono); font-size: 0.84em; background: var(--ai-panel-alt); padding: 2px 6px; border-radius: 5px; color: var(--ai-accent); }

/* ---------- Table ---------- */
.tbl { width: 100%; border-collapse: collapse; font-size: 0.88rem; }
.tbl th, .tbl td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--ai-border); }
.tbl th { color: var(--ai-subtle); font-weight: 600; font-size: 0.74rem; text-transform: uppercase; letter-spacing: 0.06em; }
.tbl td { color: var(--ai-body); }
.tbl tr:hover td { background: var(--ai-surface); }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .feature { grid-template-columns: 1fr; gap: 28px; }
  .footer__grid { grid-template-columns: 1fr 1fr; gap: 28px; }
  .footer__brand { grid-column: span 2; }
}
@media (max-width: 760px) {
  .nav__links { display: none; }
  .nav__toggle { display: inline-flex; }
  .nav__cta { display: none; }
  .nav__cta-mobile { display: inline-flex; width: 100%; justify-content: center; margin-top: 6px; }
  .nav__inner { gap: 14px; }
  .mega { position: static; transform: none; width: 100%; }
  .feature__spec { grid-template-columns: 1fr; }
  .footer__grid { grid-template-columns: 1fr; }
  .footer__brand { grid-column: auto; }
  .section { padding: 60px 0; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}