/* Syncetix marketing site — "The Loop" design system v1 (see DESIGN.md at repo root).
   Zero-JS site: theme follows the OS via prefers-color-scheme; dark is the brand-first presentation. */

@font-face {
  font-family: 'Archivo';
  font-style: normal;
  font-weight: 400 800;
  font-stretch: 100% 125%;
  font-display: swap;
  src: url('/fonts/archivo.woff2') format('woff2');
}
@font-face {
  font-family: 'Spline Sans Mono';
  font-style: normal;
  font-weight: 400 500;
  font-display: swap;
  src: url('/fonts/spline-sans-mono.woff2') format('woff2');
}

:root {
  /* Harbor dark (default presentation) */
  --canvas: #0B1220;
  --surface: #111C30;
  --raised: #182740;
  --hairline: rgba(151, 177, 255, 0.11);
  --hairline-strong: rgba(151, 177, 255, 0.22);
  --ink: #E8EEF7;
  --ink-soft: #C6D2E5;
  --muted: #94A5C2;
  --teal: #2DD4BF;
  --teal-ink: #04211C;
  --teal-hover: #43E0CC;
  --teal-dim: rgba(45, 212, 191, 0.14);
  --blue: #82A9FF;
  --blue-strong: #2563EB;
  --blue-dim: rgba(96, 140, 255, 0.16);
  --hero-a: #0B1220;
  --hero-b: #13233F;
  --ease: cubic-bezier(0.23, 1, 0.32, 1);
  color-scheme: dark;
}
@media (prefers-color-scheme: light) {
  :root {
    --canvas: #F6F8FB;
    --surface: #FFFFFF;
    --raised: #EEF2F8;
    --hairline: rgba(19, 35, 63, 0.12);
    --hairline-strong: rgba(19, 35, 63, 0.24);
    --ink: #13233F;
    --ink-soft: #33455F;
    --muted: #51617C;
    --teal: #0F766E;
    --teal-ink: #FFFFFF;
    --teal-hover: #0D9488;
    --teal-dim: rgba(13, 148, 136, 0.10);
    --blue: #2050C8;
    --blue-dim: rgba(37, 99, 235, 0.10);
    color-scheme: light;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--canvas);
  color: var(--ink);
  font: 400 16px/1.65 'Archivo', system-ui, sans-serif;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3 { margin: 0; text-wrap: balance; letter-spacing: -0.02em; }
p { margin: 0; }
a { color: var(--teal); }
.mono { font-family: 'Spline Sans Mono', ui-monospace, monospace; font-variant-numeric: tabular-nums; }

.wrap { max-width: 1520px; margin: 0 auto; padding: 0 clamp(24px, 3.5vw, 56px); }

/* ---------- Header ---------- */
.nav {
  display: flex; align-items: center; gap: 22px;
  padding-top: 20px; padding-bottom: 20px;
}
.logo {
  display: flex; align-items: center; gap: 10px;
  color: var(--ink); text-decoration: none; font-weight: 650; font-size: 18px; letter-spacing: -0.01em;
  white-space: nowrap;
}
.logo svg { width: 30px; height: 30px; flex: none; }
.nav-links { margin-left: auto; display: flex; align-items: center; gap: 8px; }
.nav-links a { color: var(--ink-soft); text-decoration: none; font-size: 14px; font-weight: 500; padding: 8px 12px; border-radius: 8px; transition: background 150ms var(--ease), color 150ms var(--ease); }
.nav-links a:hover { background: var(--raised); color: var(--ink); }
.nav-links a:focus-visible, .btn:focus-visible, a:focus-visible { outline: 2px solid var(--teal); outline-offset: 2px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; text-decoration: none; border-radius: 8px; font-weight: 600; font-size: 14.5px;
  padding: 11px 20px; transition: transform 150ms var(--ease), background 150ms var(--ease);
}
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--teal); color: var(--teal-ink) !important; }
.btn-primary:hover { background: var(--teal-hover); }
.btn-ghost { color: var(--ink); border: 1px solid var(--hairline-strong); }
.btn-ghost:hover { background: var(--raised); }

/* ---------- Hero ---------- */
.hero {
  position: relative; overflow: hidden;
  background: linear-gradient(160deg, var(--hero-a) 0%, #101C36 55%, var(--hero-b) 100%);
  padding: clamp(64px, 10vw, 128px) 0 clamp(56px, 8vw, 104px);
  color: #E8EEF7;
}
.hero .looplines { position: absolute; inset: 0; width: 100%; height: 100%; opacity: 0.5; pointer-events: none; }
.hero .wrap { position: relative; }
.hero h1 {
  font-stretch: 125%; font-weight: 750; line-height: 1.05;
  font-size: clamp(34px, 5.6vw, 62px); max-width: 16ch;
}
.hero h1 .out { color: #82A9FF; }
.hero h1 .back { color: #2DD4BF; }
.hero .tagline { margin-top: 20px; font-size: clamp(15.5px, 1.8vw, 17.5px); color: #B9C6DC; max-width: 54ch; }
.hero .cta { margin-top: 30px; display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.hero .btn-primary { background: #2DD4BF; color: #04211C !important; }
.hero .btn-primary:hover { background: #43E0CC; }
.hero .btn-ghost { color: #E8EEF7; border-color: rgba(151, 177, 255, 0.35); }
.hero .btn-ghost:hover { background: rgba(151, 177, 255, 0.12); }
.hero .quiet { font-size: 13px; color: #8FA0BC; }
.hero .proof {
  margin-top: 44px; display: flex; gap: 28px; flex-wrap: wrap;
  font-family: 'Spline Sans Mono', monospace; font-size: 12.5px; color: #8FA0BC;
}
.hero .proof b { color: #E8EEF7; font-weight: 500; }

/* ---------- Sections ---------- */
section { padding: clamp(48px, 7vw, 84px) 0; }
.lede { color: var(--ink-soft); max-width: 62ch; margin-top: 14px; font-size: 16.5px; }
h2 { font-size: clamp(24px, 3vw, 32px); font-weight: 700; font-stretch: 125%; }

/* Feature zig-zag: alternating two-column rows, never the 3-equal-card grid. */
.flow-row {
  display: grid; grid-template-columns: 1fr 1fr; gap: clamp(24px, 4vw, 56px);
  align-items: center; padding: clamp(28px, 4vw, 44px) 0; border-top: 1px solid var(--hairline);
}
.flow-row:first-of-type { border-top: 0; }
.flow-row.rev .copy { order: 2; }
.flow-row h3 { font-size: 19px; font-weight: 650; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.flow-row p { color: var(--ink-soft); margin-top: 10px; font-size: 15px; max-width: 48ch; }
.flow-row .art {
  border: 1px solid var(--hairline); border-radius: 12px; background: var(--surface);
  padding: 18px; font-family: 'Spline Sans Mono', monospace; font-size: 12.5px; color: var(--muted);
  display: grid; gap: 10px;
}
.art .line { display: flex; justify-content: space-between; gap: 12px; border-bottom: 1px solid var(--hairline); padding-bottom: 9px; }
.art .line:last-child { border-bottom: 0; padding-bottom: 0; }
.art .line b { color: var(--ink); font-weight: 500; }
.dirchip {
  display: inline-flex; align-items: center; gap: 6px; font-weight: 500; font-size: 12px;
  padding: 3px 10px; border-radius: 999px; font-stretch: 100%;
}
.dirchip.out { color: var(--blue); background: var(--blue-dim); }
.dirchip.back { color: var(--teal); background: var(--teal-dim); }
.ok { color: #34D399; }
@media (prefers-color-scheme: light) { .ok { color: #047857; } }

/* ---------- Prose pages (about, legal) ---------- */
.page-title { padding-top: clamp(40px, 6vw, 64px); }
.page-title h1 { font-size: clamp(28px, 4vw, 40px); font-weight: 700; font-stretch: 125%; }
.page-title .meta { margin-top: 10px; font-family: 'Spline Sans Mono', monospace; font-size: 12.5px; color: var(--muted); }
/* Legal documents: side rail + prose grid, so a desktop screen holds a document, not a phone
   column floating in space. The rail lists every agreement with the current one marked. */
.legal-grid { display: grid; grid-template-columns: 240px minmax(0, 1fr) 230px; gap: clamp(40px, 4vw, 72px); align-items: start; padding-bottom: 72px; }
.legal-rail { position: sticky; top: 28px; display: grid; gap: 2px; border-left: 1px solid var(--hairline); padding-left: 18px; }
.legal-rail b { font-size: 12.5px; font-weight: 600; color: var(--ink); letter-spacing: .02em; margin-bottom: 6px; }
.legal-rail a { color: var(--muted); text-decoration: none; font-size: 13.5px; padding: 5px 0; }
.legal-rail a:hover { color: var(--ink); }
.legal-rail a[aria-current="page"] { color: var(--teal); font-weight: 500; }
.legal-grid .prose { padding-bottom: 0; }

.prose { max-width: 82ch; padding-bottom: 72px; }
.prose h2 { font-size: 21px; font-weight: 650; font-stretch: 100%; margin: 38px 0 0; }
.prose h3 { font-size: 16.5px; font-weight: 650; margin: 26px 0 0; }
.prose p, .prose li { color: var(--ink-soft); font-size: 16.5px; line-height: 1.68; }
.prose p { margin-top: 12px; }
.prose ul, .prose ol { margin: 12px 0 0; padding-left: 22px; }
.prose li { margin-top: 7px; }
.prose strong { color: var(--ink); }
.prose .callout {
  margin-top: 18px; border: 1px solid var(--hairline-strong); border-radius: 12px;
  background: var(--surface); padding: 14px 18px; font-size: 14px; color: var(--ink-soft);
}

/* Legal hub list — two columns on desktop so the hub fills the page it owns. */
.legal-list { display: grid; gap: 12px; margin-top: 26px; grid-template-columns: repeat(auto-fit, minmax(340px, 1fr)); max-width: 900px; }
.legal-list a {
  display: flex; justify-content: space-between; align-items: baseline; gap: 16px;
  border: 1px solid var(--hairline); border-radius: 12px; background: var(--surface);
  padding: 16px 20px; text-decoration: none; transition: background 150ms var(--ease), border-color 150ms var(--ease);
}
.legal-list a:hover { background: var(--raised); border-color: var(--hairline-strong); }
.legal-list b { color: var(--ink); font-weight: 600; font-size: 15px; }
.legal-list span { font-family: 'Spline Sans Mono', monospace; font-size: 12px; color: var(--muted); white-space: nowrap; }

/* Dot rows (feature checks, changelog entries) + numbered step rows (docs) */
.dotrow { display: flex; gap: 11px; align-items: baseline; padding: 10px 0; border-top: 1px solid var(--hairline); font-size: 15px; color: var(--ink-soft); }
.dotrow .dot { width: 8px; height: 8px; border-radius: 50%; flex: none; align-self: center; background: currentColor; }
.dotrow b { color: var(--ink); font-weight: 600; }
.warn { color: #FBBF24; }
@media (prefers-color-scheme: light) { .warn { color: #A16207; } }
.steplist { list-style: none; margin: 14px 0 0; padding: 0; }
.steplist li { display: flex; gap: 14px; padding: 13px 0; border-top: 1px solid var(--hairline); }
.steplist .n { font-family: 'Spline Sans Mono', monospace; font-size: 13px; color: var(--teal); flex: none; padding-top: 2px; }
.steplist a { font-weight: 550; text-decoration: none; color: var(--ink); }
.steplist a:hover { color: var(--teal); }
.steplist p { margin-top: 3px; font-size: 13.5px; color: var(--muted); }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(32px, 5vw, 80px); align-items: start; }
@media (max-width: 860px) { .two-col { grid-template-columns: 1fr; } }
.chips-line { margin-top: 6px; display: flex; gap: 8px; flex-wrap: wrap; }

/* ---------- Footer ---------- */
footer { border-top: 1px solid var(--hairline); padding: 36px 0 48px; margin-top: 24px; }
.foot { display: flex; gap: 28px; flex-wrap: wrap; align-items: flex-start; }
.foot .col { display: grid; gap: 8px; min-width: 150px; }
.foot .col b { font-size: 12.5px; font-weight: 600; color: var(--ink); }
.foot a { color: var(--muted); text-decoration: none; font-size: 13px; }
.foot a:hover { color: var(--ink); }
.foot .brand { margin-right: auto; max-width: 280px; }
.foot .brand p { color: var(--muted); font-size: 12.5px; margin-top: 10px; }

@media (max-width: 760px) {
  .flow-row { grid-template-columns: 1fr; }
  .flow-row.rev .copy { order: 0; }
}
.toc-rail { position: sticky; top: 28px; display: grid; gap: 2px; border-left: 1px solid var(--hairline); padding-left: 18px; }
.toc-rail b { font-size: 12.5px; font-weight: 600; color: var(--ink); letter-spacing: .02em; margin-bottom: 6px; }
.toc-rail a { color: var(--muted); text-decoration: none; font-size: 13px; padding: 4px 0; line-height: 1.35; }
.toc-rail a:hover { color: var(--ink); }

@media (max-width: 1100px) {
  .legal-grid { grid-template-columns: 240px minmax(0, 1fr); }
  .toc-rail { display: none; }
}
@media (max-width: 900px) {
  .legal-grid { grid-template-columns: 1fr; gap: 8px; }
  .legal-rail { position: static; border-left: 0; padding-left: 0; grid-auto-flow: column; grid-auto-columns: max-content; gap: 14px; overflow-x: auto; padding-bottom: 8px; }
  .legal-rail b { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  * { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; }
  html { scroll-behavior: auto; }
}