/* QUILL documentation site - accessible, responsive, theme-aware.
   Design goals mirror the product: high contrast, keyboard-first focus
   visibility, reduced-motion friendly, readable measure, no layout that
   depends on color alone. */

:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --surface: #f5f7fa;
  --surface-2: #eef1f6;
  --border: #d3d9e3;
  --text: #1a1f29;
  --muted: #4a5568;
  --accent: #1f5fbf;
  --accent-strong: #16448c;
  --accent-contrast: #ffffff;
  --focus: #b8540a;
  --maxw: 72rem;
  --measure: 42rem;
  --radius: 12px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0e1117;
    --surface: #161b22;
    --surface-2: #1c2430;
    --border: #2a3340;
    --text: #e8edf4;
    --muted: #aab4c2;
    --accent: #6fb1ff;
    --accent-strong: #9ccaff;
    --accent-contrast: #0e1117;
    --focus: #ffb86b;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation-duration: 0.001ms !important; transition-duration: 0.001ms !important; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  font-size: 1.05rem;
}

/* Skip link for keyboard / screen-reader users. */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--accent);
  color: var(--accent-contrast);
  padding: 0.6rem 1rem;
  border-radius: 0 0 var(--radius) 0;
  z-index: 100;
}
.skip-link:focus { left: 0; }

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { color: var(--accent-strong); }

:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 4px;
}

/* Layout */
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 1.25rem; }

header.site {
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  position: sticky;
  top: 0;
  z-index: 10;
}
header.site .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-top: 0.85rem;
  padding-bottom: 0.85rem;
  flex-wrap: wrap;
}
.brand { display: flex; align-items: baseline; gap: 0.6rem; font-weight: 700; font-size: 1.25rem; text-decoration: none; color: var(--text); }
.brand .quill { color: var(--accent); letter-spacing: 0.02em; }
.brand .tag { font-size: 0.8rem; font-weight: 500; color: var(--muted); }

nav.site ul { list-style: none; display: flex; gap: 1.1rem; margin: 0; padding: 0; flex-wrap: wrap; }
nav.site a { font-weight: 600; text-decoration: none; }
nav.site a:hover, nav.site a:focus-visible { text-decoration: underline; }

/* Hero */
.hero { padding: 3.5rem 0 2.5rem; }
.hero h1 { font-size: clamp(2rem, 5vw, 3.1rem); line-height: 1.15; margin: 0 0 0.75rem; }
.hero .lede { font-size: 1.2rem; color: var(--muted); max-width: var(--measure); }
.hero .acronym { margin-top: 1.25rem; font-size: 1rem; color: var(--text); }
.hero .acronym strong { color: var(--accent); }

.cta { margin-top: 1.75rem; display: flex; gap: 0.75rem; flex-wrap: wrap; }
.btn {
  display: inline-block;
  background: var(--accent);
  color: var(--accent-contrast);
  padding: 0.7rem 1.2rem;
  border-radius: var(--radius);
  font-weight: 700;
  text-decoration: none;
  border: 2px solid transparent;
}
.btn:hover { background: var(--accent-strong); color: var(--accent-contrast); }
.btn.secondary {
  background: transparent;
  color: var(--accent);
  border-color: var(--border);
}
.btn.secondary:hover { border-color: var(--accent); }

/* Section */
section.band { padding: 2.5rem 0; border-top: 1px solid var(--border); }
section.band h2 { font-size: 1.7rem; margin: 0 0 0.4rem; }
section.band > .wrap > p.intro { color: var(--muted); max-width: var(--measure); margin-top: 0; }

/* Cards */
.cards {
  display: grid;
  gap: 1.1rem;
  grid-template-columns: repeat(auto-fit, minmax(16rem, 1fr));
  margin-top: 1.5rem;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.25rem 1.35rem;
  display: flex;
  flex-direction: column;
}
.card h3 { margin: 0 0 0.4rem; font-size: 1.2rem; }
.card h3 a { text-decoration: none; }
.card h3 a:hover { text-decoration: underline; }
.card p { margin: 0 0 0.9rem; color: var(--muted); }
.card ul { margin: 0; padding-left: 1.1rem; }
.card ul li { margin: 0.2rem 0; }
.card .more { margin-top: auto; font-weight: 600; }

/* Feature list */
.features { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fit, minmax(15rem, 1fr)); margin-top: 1.25rem; }
.feature { background: var(--surface-2); border-radius: var(--radius); padding: 1rem 1.1rem; border: 1px solid var(--border); }
.feature h3 { margin: 0 0 0.35rem; font-size: 1.05rem; }
.feature p { margin: 0; color: var(--muted); font-size: 0.97rem; }

/* Prose pages (FAQ, docs hub body) */
main.prose { padding: 2.5rem 0 3.5rem; }
.prose h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); margin: 0 0 0.5rem; }
.prose .lede { color: var(--muted); font-size: 1.15rem; max-width: var(--measure); }
.prose h2 { margin-top: 2.2rem; font-size: 1.5rem; border-top: 1px solid var(--border); padding-top: 1.4rem; }
.prose h3 { margin-top: 1.6rem; font-size: 1.15rem; }
.prose p, .prose li { max-width: var(--measure); }
.prose code {
  background: var(--surface-2);
  padding: 0.12em 0.4em;
  border-radius: 6px;
  font-size: 0.92em;
  font-family: "Cascadia Code", "Fira Code", Consolas, ui-monospace, monospace;
}
.prose pre {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  overflow-x: auto;
}
.prose pre code { background: none; padding: 0; }

/* FAQ details/summary */
.faq details {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 0.7rem 0;
  background: var(--surface);
}
.faq details[open] { background: var(--surface-2); }
.faq summary {
  cursor: pointer;
  padding: 0.9rem 1.1rem;
  font-weight: 600;
  font-size: 1.05rem;
  list-style: none;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::before { content: "\25B8\00a0"; color: var(--accent); }
.faq details[open] summary::before { content: "\25BE\00a0"; }
.faq summary:hover { color: var(--accent); }
.faq details > *:not(summary) { padding: 0 1.1rem 0.4rem; max-width: var(--measure); }
.faq .toc { columns: 2; gap: 2rem; }
@media (max-width: 40rem) { .faq .toc { columns: 1; } }

/* Footer */
footer.site {
  border-top: 1px solid var(--border);
  background: var(--surface);
  padding: 2rem 0 2.5rem;
  margin-top: 2rem;
  color: var(--muted);
}
footer.site .wrap { display: flex; flex-wrap: wrap; gap: 1.5rem; justify-content: space-between; }
footer.site nav ul { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 0.35rem; }
footer.site h4 { margin: 0 0 0.5rem; font-size: 0.95rem; color: var(--text); }
footer.site .note { max-width: 22rem; font-size: 0.92rem; }

.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

/* Requirement note under hero CTA */
.hero .req-note {
  font-size: 0.875rem;
  color: var(--muted);
  margin-top: 0.75rem;
  max-width: var(--measure);
}

/* Time-sensitive callout band (Office Hours, release announcement) */
.band.callout {
  background: color-mix(in srgb, var(--accent) 8%, var(--bg));
  border-top: 2px solid var(--accent);
}
.band.callout h2 { color: var(--accent-strong); }

@media (prefers-color-scheme: dark) {
  .band.callout { background: color-mix(in srgb, var(--accent) 13%, var(--bg)); }
  .band.callout h2 { color: var(--accent); }
}

/* Download card in hero area */
.download-links { list-style: none; padding: 0; margin: 0.5rem 0 0; display: flex; flex-direction: column; gap: 0.3rem; }
.download-links li::before { content: none; }

/* doc-links already defined above; keep for compat */
.doc-links { list-style: none; padding: 0; margin: 0.4rem 0 0; display: flex; flex-direction: column; gap: 0.2rem; }

/* Nav download dropdown using native details/summary */
.nav-has-sub { position: relative; }
.nav-dropdown { display: inline; }
.nav-dropdown > summary {
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  color: var(--accent);
}
.nav-dropdown > summary::-webkit-details-marker { display: none; }
.nav-dropdown > summary::after { content: " \25BE"; font-size: 0.75em; }
.nav-dropdown > summary:hover { text-decoration: underline; }
.nav-dropdown > summary:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 4px;
}
.nav-dropdown > ul {
  position: absolute;
  top: calc(100% + 0.4rem);
  left: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.35rem 0;
  list-style: none;
  margin: 0;
  min-width: 13rem;
  box-shadow: 0 4px 14px rgba(0,0,0,0.12);
  z-index: 20;
}
.nav-dropdown > ul a { display: block; padding: 0.45rem 1rem; white-space: nowrap; }