/* Hallmark · pre-emit critique: P5 H5 E4 S5 R5 V4
 * Hallmark · macrostructure: Marquee Hero (+ Conversational FAQ below fold)
 * genre: modern-minimal · theme: Cobalt · tone: technical · anchor hue: cool (265)
 * nav: N9 edge-aligned (wordmark left, single CTA right, no link row)
 * footer: Ft2 inline single line
 * enrichment: Tier A CSS art (source-vs-rendered type comparison, no chrome)
 * axes: paper light · display grotesk-sans · accent cool
 */

:root {
  /* colour */
  --color-paper:      oklch(97.5% 0.004 265);
  --color-paper-2:    oklch(94.5% 0.008 265);
  --color-paper-3:    oklch(90%   0.012 265);
  --color-ink:        oklch(21%   0.021 265);
  --color-ink-2:      oklch(46%   0.017 265);
  --color-accent:     oklch(48%   0.183 265);
  --color-accent-ink: oklch(97.5% 0.004 265);
  --color-rule:       oklch(87%   0.014 265);
  --color-focus:      oklch(48%   0.183 265);

  /* type */
  --font-display: "Space Grotesk", ui-sans-serif, system-ui, sans-serif;
  --font-body:    "IBM Plex Sans", ui-sans-serif, system-ui, sans-serif;
  --font-mono:    "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  --text-marquee: clamp(2.75rem, 8.5vw, 7rem);
  --text-3xl:     clamp(1.75rem, 3.2vw, 2.5rem);
  --text-xl:      clamp(1.15rem, 1.7vw, 1.4rem);
  --text-base:    1.0625rem;
  --text-sm:      0.9375rem;
  --text-xs:      0.8125rem;

  /* space — 4pt */
  --space-xs:  0.5rem;
  --space-sm:  1rem;
  --space-md:  1.5rem;
  --space-lg:  2.5rem;
  --space-xl:  4rem;
  --space-2xl: 6rem;

  --rule-hair:  1px;
  --rule-thick: 4px;
  --radius-sm:  4px;

  --ease-out:    cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
  --dur-fast:    140ms;
  --dur-mid:     220ms;

  --measure: 34rem;
  --gutter: clamp(1.25rem, 5vw, 5rem);
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-paper:      oklch(17% 0.017 265);
    --color-paper-2:    oklch(21% 0.021 265);
    --color-paper-3:    oklch(26% 0.024 265);
    --color-ink:        oklch(95% 0.006 265);
    --color-ink-2:      oklch(72% 0.018 265);
    --color-accent:     oklch(74% 0.142 265);
    --color-accent-ink: oklch(17% 0.017 265);
    --color-rule:       oklch(31% 0.021 265);
    --color-focus:      oklch(74% 0.142 265);
  }
}

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

html, body {
  overflow-x: clip;
  margin: 0;
}

body {
  background: var(--color-paper);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, summary {
  font-family: var(--font-display);
  font-style: normal;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.08;
  overflow-wrap: anywhere;
  min-width: 0;
}

a { color: var(--color-accent); text-underline-offset: 0.18em; }
a:hover { text-decoration-thickness: 2px; }

:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
  border-radius: 2px;
}

code, kbd, pre { font-family: var(--font-mono); font-size: 0.9em; }

.skip {
  position: absolute;
  left: -9999px;
}
.skip:focus {
  left: var(--gutter);
  top: var(--space-xs);
  z-index: 10;
  background: var(--color-accent);
  color: var(--color-accent-ink);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
}

/* ---- N9 edge-aligned nav ------------------------------------------- */

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-sm) var(--gutter);
  border-bottom: var(--rule-hair) solid var(--color-rule);
  flex-wrap: wrap;
}

.topbar__mark {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-ink);
  text-decoration: none;
  white-space: nowrap;
}

.topbar__glyph {
  width: 1.05rem;
  height: 1.05rem;
  border-radius: 3px;
  background: var(--color-accent);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 0 100%);
  position: relative;
}
.topbar__glyph::after {
  content: "";
  position: absolute;
  inset: 0;
  background: var(--color-accent-ink);
  clip-path: polygon(36% 26%, 76% 50%, 36% 74%);
}

/* N9: wordmark hard-left, one CTA hard-right, nothing between. The absence of
   a link row is the archetype; secondary destinations live in the footer. */

.topbar__cta {
  color: var(--color-accent-ink) !important;
  background: var(--color-accent);
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  transition: transform var(--dur-fast) var(--ease-out);
}
.topbar__cta:hover { transform: translateY(-1px); }
.topbar__cta:active { transform: translateY(0); }

/* ---- Marquee hero -------------------------------------------------- */

.marquee {
  padding: clamp(var(--space-xl), 12vh, var(--space-2xl)) var(--gutter);
}

.marquee h1 {
  font-size: var(--text-marquee);
  margin: 0;
  max-width: 16ch;
}

.marquee__accent { color: var(--color-accent); }

.marquee__meta {
  margin-top: var(--space-lg);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-2);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.rule-thick {
  border: 0;
  border-top: var(--rule-thick) solid var(--color-ink);
  margin: 0;
}

/* ---- below fold ---------------------------------------------------- */

.band { padding: var(--space-2xl) var(--gutter); }
.band + .band { border-top: var(--rule-hair) solid var(--color-rule); }
.band--tint { background: var(--color-paper-2); }

.band h2 {
  font-size: var(--text-3xl);
  margin: 0 0 var(--space-md);
  max-width: 22ch;
}

.band p { max-width: var(--measure); }

.lede {
  font-size: var(--text-xl);
  color: var(--color-ink-2);
  max-width: 42ch;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-lg);
  align-items: center;
}

.btn {
  display: inline-block;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--text-base);
  padding: 0.7rem 1.3rem;
  border-radius: var(--radius-sm);
  text-decoration: none;
  white-space: nowrap;
  transition: transform var(--dur-fast) var(--ease-out),
              background-color var(--dur-fast) var(--ease-out);
}

.btn--primary {
  background: var(--color-accent);
  color: var(--color-accent-ink);
  border: var(--rule-hair) solid var(--color-accent);
}
.btn--primary:hover { transform: translateY(-1px); }
.btn--primary:active { transform: translateY(0); }

.btn--ghost {
  border: var(--rule-hair) solid var(--color-rule);
  color: var(--color-ink);
}
.btn--ghost:hover { background: var(--color-paper-3); }

.cta-note {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-2);
}

/* ---- Tier A CSS art: source vs rendered ---------------------------- */

.compare {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: var(--space-md);
  margin-top: var(--space-lg);
  align-items: stretch;
}

.compare__pane {
  border: var(--rule-hair) solid var(--color-rule);
  border-radius: var(--radius-sm);
  padding: var(--space-md);
  background: var(--color-paper);
  min-width: 0;
  overflow: hidden;
}

.compare__label {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-ink-2);
  margin: 0 0 var(--space-sm);
}

.compare__code {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  line-height: 1.75;
  color: var(--color-ink-2);
  margin: 0;
  white-space: pre;
  overflow-x: auto;
}

.compare__tag { color: var(--color-accent); }

.compare__render h3 {
  font-size: 1.35rem;
  margin: 0 0 0.4rem;
}
.compare__render p {
  margin: 0;
  font-size: var(--text-sm);
  color: var(--color-ink-2);
}
.compare__swatches { display: flex; gap: 0.4rem; margin-top: var(--space-sm); }
.compare__swatches span {
  width: 1.6rem; height: 1.6rem; border-radius: 3px;
  background: var(--color-accent);
}
.compare__swatches span:nth-child(2) { background: var(--color-ink-2); opacity: 0.55; }
.compare__swatches span:nth-child(3) { background: var(--color-paper-3); }

/* ---- spec list ----------------------------------------------------- */

.spec {
  margin: 0;
  display: grid;
  grid-template-columns: max-content minmax(0, 1fr);
  gap: var(--space-xs) var(--space-md);
  font-size: var(--text-sm);
}
.spec dt {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-ink-2);
  padding-top: 0.22rem;
}
.spec dd { margin: 0; }
.spec code {
  background: var(--color-paper-3);
  padding: 0.1rem 0.3rem;
  border-radius: 3px;
}

/* ---- Conversational FAQ -------------------------------------------- */

.faq { max-width: 46rem; }

.faq details {
  border-top: var(--rule-hair) solid var(--color-rule);
  padding: var(--space-sm) 0;
}
.faq details:last-of-type { border-bottom: var(--rule-hair) solid var(--color-rule); }

.faq summary {
  cursor: pointer;
  font-size: var(--text-xl);
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: var(--space-sm);
}
.faq summary::-webkit-details-marker { display: none; }

.faq summary::after {
  content: "+";
  font-family: var(--font-mono);
  color: var(--color-accent);
  font-weight: 500;
  flex: none;
}
.faq details[open] summary::after { content: "\2013"; }

.faq__answer {
  display: grid;
  grid-template-rows: 1fr;
  margin-top: var(--space-sm);
}
.faq__answer > div { overflow: hidden; }
.faq__answer p { margin: 0 0 var(--space-sm); max-width: var(--measure); }
.faq__answer p:last-child { margin-bottom: 0; }

@media (prefers-reduced-motion: no-preference) {
  .faq details[open] .faq__answer {
    animation: open var(--dur-mid) var(--ease-out);
  }
  @keyframes open {
    from { grid-template-rows: 0fr; opacity: 0; }
    to   { grid-template-rows: 1fr; opacity: 1; }
  }
}

/* ---- prose (privacy policy) ---------------------------------------- */

.prose {
  max-width: 42rem;
  padding: var(--space-xl) var(--gutter) var(--space-2xl);
  margin: 0 auto;
}
.prose h1 { font-size: var(--text-3xl); margin-top: 0; }
.prose h2 {
  font-size: var(--text-xl);
  margin-top: var(--space-xl);
  padding-top: var(--space-sm);
  border-top: var(--rule-hair) solid var(--color-rule);
}
.prose ul { padding-left: 1.1rem; }
.prose li { margin-bottom: var(--space-xs); }
.prose code {
  background: var(--color-paper-3);
  padding: 0.1rem 0.3rem;
  border-radius: 3px;
}

/* ---- Ft2 inline single line ---------------------------------------- */

.colophon {
  border-top: var(--rule-hair) solid var(--color-rule);
  padding: var(--space-md) var(--gutter);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--color-ink-2);
}
.colophon p { margin: 0; }
.colophon a { color: var(--color-ink-2); }
.colophon a:hover { color: var(--color-accent); }

/* ---- mobile -------------------------------------------------------- */

@media (max-width: 720px) {
  .compare { grid-template-columns: minmax(0, 1fr); }
  .spec { grid-template-columns: minmax(0, 1fr); gap: 0.15rem var(--space-md); }
  .spec dd { margin-bottom: var(--space-sm); }
  .topbar { gap: var(--space-sm); }
}

@media (max-width: 380px) {
  .topbar__mark { font-size: var(--text-xs); }
}