/* ==========================================================================
   Olsie Discovery Archive — Design System
   A contemporary technology-museum aesthetic: ivory grounds, navy structure,
   copper and cobalt accents, editorial serif type for reading, grotesque
   sans for navigation and interface chrome.
   ========================================================================== */

:root {
  color-scheme: dark;
  forced-color-adjust: none;
  --ivory: #121a26;
  --ivory-deep: #0d131d;
  --paper: #1c2838;
  --navy: #0b1f3a;
  --navy-deep: #081528;
  --navy-soft: #1c3458;
  --copper: #b5622e;
  --copper-light: #d98a4f;
  --copper-text: #8a4a1f; /* dark copper kept for small light-chip badges and filled buttons only */
  --heading: #f0e6d2; /* light cream headings/labels on the dark ground */
  --link: #9fc1fb; /* light cobalt for body links on the dark ground */
  --cobalt: #2a52be;
  --cobalt-deep: #1d3b8a;
  --ink: #e7e1d2;
  --ink-soft: #aaa392;
  --line: #2c3a4f;
  --line-strong: #44566e;
  --success: #2f6d4f;

  --font-serif: 'Source Serif 4', Georgia, 'Times New Roman', serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  --radius: 2px;
  --shadow-card: 0 1px 2px rgba(11, 31, 58, 0.06), 0 6px 20px rgba(11, 31, 58, 0.06);
  --shadow-lift: 0 10px 30px rgba(11, 31, 58, 0.14);
  --max-width: 1240px;
}

/*
 * The archive always renders in its designed dark palette (deep navy ground,
 * cream headings, copper/cobalt accents) regardless of the visitor's OS or
 * browser preference — this is a deliberate editorial/museum-at-night look,
 * not a themeable UI, so there is no automatic prefers-color-scheme switch.
 */

* { box-sizing: border-box; }
html { scroll-behavior: smooth; color-scheme: dark; forced-color-adjust: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; }
}

body {
  margin: 0;
  background: var(--ivory);
  color: var(--ink);
  font-family: var(--font-serif);
  font-size: 1.05rem;
  line-height: 1.65;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--link); }
a:hover { color: var(--copper-light); }
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible {
  outline: 3px solid var(--copper);
  outline-offset: 2px;
}

h1, h2, h3, h4 { font-family: var(--font-serif); color: var(--heading); line-height: 1.2; font-weight: 700; margin: 0 0 0.6em; }
h1 { font-size: clamp(2rem, 4vw, 2.9rem); }
h2 { font-size: clamp(1.4rem, 2.6vw, 1.9rem); }
h3 { font-size: 1.25rem; }

p { margin: 0 0 1.1em; }

.wrap { max-width: var(--max-width); margin: 0 auto; padding: 0 1.5rem; }

.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: 0; background: var(--navy); color: #fff;
  padding: 0.8em 1.2em; z-index: 1000; font-family: var(--font-sans);
}
.skip-link:focus { left: 0.5rem; top: 0.5rem; }

/* ---------- Header ---------- */
.site-header {
  background: var(--navy);
  border-bottom: 4px solid var(--copper);
  position: sticky; top: 0; z-index: 100;
}
.site-header__inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1.5rem; padding: 0.85rem 1.5rem;
}
.brand { display: flex; align-items: center; gap: 0.7rem; text-decoration: none; }
.brand__mark { flex-shrink: 0; }
.brand__text { display: flex; flex-direction: column; font-family: var(--font-sans); }
.brand__name { color: #fff; font-weight: 700; font-size: 1.05rem; letter-spacing: 0.01em; }
.brand__tagline { color: var(--copper-light); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.08em; }

.nav-toggle {
  display: none; background: none; border: 1px solid var(--navy-soft); color: #fff;
  width: 42px; height: 38px; border-radius: var(--radius); cursor: pointer; position: relative;
}
.nav-toggle__bar, .nav-toggle__bar::before, .nav-toggle__bar::after {
  content: ''; position: absolute; left: 10px; right: 10px; height: 2px; background: #fff;
}
.nav-toggle__bar { top: 18px; }
.nav-toggle__bar::before { top: -6px; }
.nav-toggle__bar::after { top: 6px; }

.site-nav { display: flex; align-items: center; gap: 1.5rem; font-family: var(--font-sans); }
.site-nav ul { list-style: none; display: flex; gap: 1.3rem; margin: 0; padding: 0; }
.site-nav a { color: #e7e2d2; text-decoration: none; font-size: 0.92rem; font-weight: 500; }
.site-nav a:hover, .site-nav a:focus-visible { color: var(--copper-light); }

.nav-search { display: flex; }
.nav-search input {
  background: var(--navy-soft); border: 1px solid var(--navy-soft); color: #fff;
  padding: 0.45em 0.8em; border-radius: var(--radius) 0 0 var(--radius); font-family: var(--font-sans);
  width: 190px; font-size: 0.85rem;
}
.nav-search input::placeholder { color: #a9b6cc; }
.nav-search button {
  background: var(--copper); border: 1px solid var(--copper); color: #fff;
  padding: 0 0.8em; border-radius: 0 var(--radius) var(--radius) 0; cursor: pointer;
}

@media (max-width: 900px) {
  .nav-toggle { display: block; }
  .site-nav {
    display: none; position: absolute; top: 100%; left: 0; right: 0; background: var(--navy-deep);
    flex-direction: column; align-items: stretch; padding: 1rem 1.5rem 1.5rem; border-top: 1px solid var(--navy-soft);
  }
  .site-nav.is-open { display: flex; }
  .site-nav ul { flex-direction: column; gap: 0; }
  .site-nav ul li { border-bottom: 1px solid var(--navy-soft); }
  .site-nav ul a { display: block; padding: 0.8em 0; }
  .nav-search { margin-top: 1rem; }
  .nav-search input { width: 100%; }
}

/* ---------- Hero ---------- */
.hero {
  background: var(--navy); color: #f1ece0; position: relative; overflow: hidden;
  border-bottom: 1px solid var(--navy-soft);
}
.hero__inner { padding: 4rem 1.5rem 3.5rem; display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 3rem; align-items: center; }
.hero__eyebrow { font-family: var(--font-sans); text-transform: uppercase; letter-spacing: 0.14em; color: var(--copper-light); font-size: 0.8rem; margin-bottom: 1rem; }
.hero h1 { color: #fff; }
.hero p.lede { color: #cbd3e3; font-size: 1.15rem; max-width: 46ch; }
.hero__art { justify-self: center; }
.hero-stats { display: flex; gap: 2rem; margin-top: 2rem; font-family: var(--font-sans); }
.hero-stats strong { display: block; font-size: 1.7rem; color: var(--copper-light); }
.hero-stats span { font-size: 0.8rem; color: #b9c2d6; text-transform: uppercase; letter-spacing: 0.06em; }

@media (max-width: 820px) {
  .hero__inner { grid-template-columns: 1fr; text-align: left; }
  .hero__art { justify-self: start; max-width: 260px; }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 0.5em; font-family: var(--font-sans); font-weight: 700;
  font-size: 0.9rem; text-decoration: none; padding: 0.7em 1.3em; border-radius: var(--radius);
  border: 1px solid transparent; cursor: pointer;
}
.btn-primary { background: var(--copper-text); color: #fff; }
.btn-primary:hover { background: var(--copper); color: #fff; }
.btn-outline { background: transparent; border-color: #fff; color: #fff; }
.btn-outline:hover { background: rgba(255,255,255,0.1); color: #fff; }
.btn-navy { background: var(--navy); color: #fff; }
.btn-navy:hover { background: var(--navy-soft); color: #fff; }

/* ---------- Section scaffolding ---------- */
.section { padding: 3.5rem 0; }
.section--tight { padding: 2rem 0; }
.section--alt { background: var(--ivory-deep); }
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; margin-bottom: 1.8rem; flex-wrap: wrap; }
.section-head .kicker { font-family: var(--font-sans); text-transform: uppercase; letter-spacing: 0.1em; color: var(--copper-light); font-size: 0.78rem; font-weight: 700; }
.section-head h2 { margin: 0.2em 0 0; }

/* ---------- Category chips / icons ---------- */
.category-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }
.category-chip {
  /* Fixed light card: the category icons are drawn with navy strokes meant
     for a light ground, so this chip keeps its own light background
     regardless of the page's overall dark theme. */
  background: #fdf9f0; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.2rem 1rem; text-align: center; text-decoration: none; color: #1a1a1a;
  transition: box-shadow 0.15s, border-color 0.15s;
}
.category-chip:hover { box-shadow: var(--shadow-card); border-color: var(--copper); }
.category-chip img { margin: 0 auto 0.6rem; width: 36px; height: 36px; }
.category-chip__label { font-family: var(--font-sans); font-weight: 600; font-size: 0.88rem; display: block; }
@media (max-width: 760px) { .category-grid { grid-template-columns: repeat(2, 1fr); } }

/* ---------- Entry cards ---------- */
.entry-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.6rem; }
@media (max-width: 980px) { .entry-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) { .entry-grid { grid-template-columns: 1fr; } }

.entry-card {
  background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius);
  overflow: hidden; display: flex; flex-direction: column; text-decoration: none; color: var(--ink);
  box-shadow: var(--shadow-card); transition: transform 0.15s, box-shadow 0.15s;
}
.entry-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lift); }
.entry-card__media { aspect-ratio: 4 / 3; background: var(--ivory-deep); border-bottom: 3px solid var(--copper); }
.entry-card__body { padding: 1.1rem 1.2rem 1.3rem; display: flex; flex-direction: column; gap: 0.5rem; flex: 1; }
.entry-card__meta { font-family: var(--font-sans); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--copper-light); display: flex; gap: 0.6rem; flex-wrap: wrap; }
.entry-card__meta span { white-space: nowrap; }
.entry-card h3 { margin: 0; font-size: 1.1rem; }
.entry-card p { font-size: 0.92rem; color: var(--ink-soft); margin: 0; flex: 1; }
.entry-card__year { font-family: var(--font-sans); font-weight: 700; color: var(--heading); font-size: 0.85rem; }

.badge {
  display: inline-block; font-family: var(--font-sans); font-size: 0.68rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.06em; padding: 0.2em 0.55em; border-radius: 2px;
}
.badge--invention { background: #e4ecfb; color: var(--cobalt-deep); }
.badge--discovery { background: #f6e4d4; color: var(--copper-text); }

/* ---------- Filters / search UI ---------- */
.filter-bar {
  background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.3rem; margin-bottom: 2rem; display: grid; grid-template-columns: 1.3fr repeat(3, 1fr); gap: 1rem;
  font-family: var(--font-sans);
}
@media (max-width: 760px) { .filter-bar { grid-template-columns: 1fr; } }
.filter-bar label { display: block; font-size: 0.75rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; color: var(--heading); margin-bottom: 0.35em; }
.filter-bar input[type="search"], .filter-bar select {
  width: 100%; padding: 0.6em 0.7em; border: 1px solid var(--line-strong); border-radius: var(--radius);
  font-family: var(--font-sans); background: var(--ivory); color: var(--ink); font-size: 0.9rem;
}
.filter-results-count { font-family: var(--font-sans); color: var(--ink-soft); font-size: 0.88rem; margin-bottom: 1rem; }
.no-results { font-family: var(--font-sans); color: var(--ink-soft); padding: 2rem; text-align: center; border: 1px dashed var(--line-strong); border-radius: var(--radius); }

/* ---------- A-Z index ---------- */
.az-jump { display: flex; flex-wrap: wrap; gap: 0.4rem; font-family: var(--font-sans); margin-bottom: 2rem; }
.az-jump a {
  width: 2.1rem; height: 2.1rem; display: inline-flex; align-items: center; justify-content: center;
  background: var(--paper); border: 1px solid var(--line); border-radius: 50%; text-decoration: none;
  color: var(--heading); font-weight: 700; font-size: 0.85rem;
}
.az-jump a:hover { background: var(--navy); color: #fff; }
.az-group { margin-bottom: 2rem; scroll-margin-top: 90px; }
.az-group h2 { border-bottom: 2px solid var(--copper); padding-bottom: 0.3em; }
.az-group ul { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(2, 1fr); gap: 0.4rem 2rem; }
.az-group li a { text-decoration: none; font-size: 1rem; }
.az-group li span { color: var(--ink-soft); font-family: var(--font-sans); font-size: 0.82rem; }
@media (max-width: 600px) { .az-group ul { grid-template-columns: 1fr; } }

/* ---------- Timeline ---------- */
.timeline { position: relative; margin: 2rem 0; padding-left: 2.2rem; border-left: 3px solid var(--line-strong); }
.timeline__era { margin: 2.5rem 0 1rem; position: relative; }
.timeline__era h2 { color: var(--heading); }
.timeline__era::before {
  content: ''; position: absolute; left: -2.65rem; top: 0.3em; width: 14px; height: 14px;
  background: var(--navy); border-radius: 50%; border: 3px solid var(--ivory);
}
.timeline__item { position: relative; padding: 0 0 1.6rem 1.6rem; border-left: 1px solid var(--line); margin-left: -0.1rem; }
.timeline__item::before {
  content: ''; position: absolute; left: -7px; top: 0.3em; width: 12px; height: 12px;
  background: var(--copper); border-radius: 50%; border: 2px solid var(--ivory);
}
.timeline__item-year { font-family: var(--font-sans); font-weight: 700; color: var(--copper-light); font-size: 0.85rem; }
.timeline__item h3 { margin: 0.2em 0 0.3em; font-size: 1.05rem; }
.timeline__item h3 a { text-decoration: none; }
.timeline__item p { color: var(--ink-soft); font-size: 0.92rem; margin: 0; }

/* ---------- Entry page ---------- */
.entry-hero { background: var(--navy-deep); color: #f1ece0; }
.entry-hero__inner { padding: 2.5rem 1.5rem; display: grid; grid-template-columns: 1fr 1fr; gap: 2.5rem; align-items: center; }
.entry-hero img { border: 3px solid var(--copper); border-radius: var(--radius); }
.entry-hero .entry-card__meta { color: var(--copper-light); }
.entry-hero h1 { color: #fff; }
.entry-hero .summary { color: #d6dcec; font-size: 1.08rem; }
@media (max-width: 820px) { .entry-hero__inner { grid-template-columns: 1fr; } }

.breadcrumbs { font-family: var(--font-sans); font-size: 0.82rem; color: var(--ink-soft); padding: 1rem 0; }
.breadcrumbs a { color: var(--ink-soft); text-decoration: none; }
.breadcrumbs a:hover { color: var(--copper-light); }
.breadcrumbs .sep { margin: 0 0.4em; }

.entry-layout { display: grid; grid-template-columns: 2.2fr 1fr; gap: 3rem; align-items: start; }
@media (max-width: 900px) { .entry-layout { grid-template-columns: 1fr; } }

.entry-body section { margin-bottom: 2.2rem; }
.entry-body h2 { border-bottom: 2px solid var(--line); padding-bottom: 0.35em; }
.entry-body p { max-width: 68ch; }

.milestone-list { list-style: none; margin: 0; padding: 0; }
.milestone-list li { display: flex; gap: 1rem; padding: 0.6rem 0; border-bottom: 1px dashed var(--line); }
.milestone-list .ms-year { font-family: var(--font-sans); font-weight: 700; color: var(--copper-light); min-width: 7rem; }
.milestone-list .ms-event { color: var(--ink-soft); font-size: 0.94rem; }

.entry-sidebar { position: sticky; top: 90px; display: flex; flex-direction: column; gap: 1.5rem; }
.side-box { background: var(--paper); border: 1px solid var(--line); border-radius: var(--radius); padding: 1.2rem; font-family: var(--font-sans); }
.side-box h2 { font-size: 0.95rem; text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 0.8em; }
.side-box dl { margin: 0; font-size: 0.88rem; }
.side-box dt { font-weight: 700; color: var(--heading); margin-top: 0.6em; }
.side-box dd { margin: 0 0 0.2em; color: var(--ink-soft); }
.side-box ul { margin: 0; padding-left: 1.1em; font-size: 0.88rem; }
.side-box li { margin-bottom: 0.5em; }

.related-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.2rem; margin-top: 1rem; }
@media (max-width: 760px) { .related-grid { grid-template-columns: 1fr; } }

.refs-list { list-style: none; margin: 0; padding: 0; }
.refs-list li { padding: 0.5em 0; border-top: 1px solid var(--line); font-size: 0.92rem; }
.refs-list li:first-child { border-top: none; }

.callout {
  background: var(--ivory-deep); border-left: 4px solid var(--copper); padding: 1rem 1.2rem; border-radius: var(--radius);
  font-size: 0.95rem; color: var(--ink-soft);
}

/* ---------- Glossary ---------- */
.glossary-list dt { font-family: var(--font-sans); font-weight: 700; color: var(--heading); font-size: 1.1rem; margin-top: 1.4rem; }
.glossary-list dd { margin: 0.3em 0 0; color: var(--ink-soft); }

/* ---------- Forms ---------- */
.form-grid { display: grid; gap: 1.2rem; max-width: 640px; font-family: var(--font-sans); }
.form-grid label { font-weight: 700; font-size: 0.85rem; color: var(--heading); display: block; margin-bottom: 0.4em; }
.form-grid input, .form-grid select, .form-grid textarea {
  width: 100%; padding: 0.7em 0.8em; border: 1px solid var(--line-strong); border-radius: var(--radius);
  font-family: var(--font-sans); background: var(--paper); color: var(--ink); font-size: 0.95rem;
}
.form-grid textarea { min-height: 140px; resize: vertical; }
.form-note { font-size: 0.82rem; color: var(--ink-soft); }
.alert { padding: 1rem 1.2rem; border-radius: var(--radius); font-family: var(--font-sans); margin-bottom: 1.5rem; }
.alert--success { background: #e3f0e8; color: var(--success); border: 1px solid #bcd9c7; }
.alert--error { background: #fbe8e1; color: #8a3a1f; border: 1px solid #f0c3ae; }

/* ---------- Static/legal pages ---------- */
.prose { max-width: 72ch; }
.prose h2 { margin-top: 1.8em; }
.prose ul, .prose ol { padding-left: 1.3em; }

/* ---------- Error page ---------- */
.error-page { text-align: center; padding: 5rem 1.5rem; }
.error-page .code { font-family: var(--font-sans); font-size: 5rem; font-weight: 800; color: var(--copper); line-height: 1; }

/* ---------- Footer ---------- */
.site-footer { background: var(--navy); color: #cfd6e5; margin-top: 4rem; font-family: var(--font-sans); }
.site-footer__inner { display: grid; grid-template-columns: 1.4fr repeat(3, 1fr); gap: 2rem; padding: 3rem 1.5rem 2rem; }
.footer-brand { display: flex; gap: 0.8rem; align-items: flex-start; font-size: 0.88rem; color: #b9c2d6; }
.footer-brand strong { color: #fff; }
.footer-nav h2 { color: #fff; font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 0.9em; }
.footer-nav ul { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 0.55em; }
.footer-nav a { color: #b9c2d6; text-decoration: none; font-size: 0.9rem; }
.footer-nav a:hover { color: var(--copper-light); }
.site-footer__bottom { border-top: 1px solid var(--navy-soft); padding: 1.2rem 1.5rem; font-size: 0.8rem; color: #93a0bd; }
@media (max-width: 820px) { .site-footer__inner { grid-template-columns: 1fr 1fr; } }
@media (max-width: 540px) { .site-footer__inner { grid-template-columns: 1fr; } }