/* Atlas — shared shell styles.
   Reused by the homepage and by world pages as they are built.
   Shell elements (header, nav, footer, brand, worlds-nav) are generic;
   homepage-specific elements (tagline, intro, world-grid, world-card)
   may also appear on a future "see all worlds" surface. */

:root {
  --bg: #faf6ed;
  --ink: #1f1a14;
  --ink-soft: #3a322a;
  --muted: #6e6558;
  --rule: #d8ccb4;
  --accent: #6c2e2e;

  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Inter", system-ui, sans-serif;

  --measure: 34rem;
  --shell-max: 60rem;
  --pad-x: 1.5rem;
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: inherit;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

/* Header & nav (shell) */

.atlas-header {
  border-bottom: 1px solid var(--rule);
}

.atlas-nav {
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 1.25rem var(--pad-x);
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.brand {
  font-family: var(--serif);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: 0.005em;
}

.brand:hover { text-decoration: none; color: var(--accent); }

.worlds-nav {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 1.75rem;
  font-family: var(--sans);
  font-size: 0.9rem;
  color: var(--muted);
}

.worlds-nav a:hover { color: var(--ink); }

/* Main content area */

.atlas-main {
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 4.5rem var(--pad-x) 6rem;
}

/* Homepage opening */

.opening {
  max-width: var(--measure);
  margin-bottom: 4.5rem;
}

.tagline {
  font-family: var(--serif);
  font-size: 2.25rem;
  line-height: 1.15;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0 0 1.25rem;
}

.intro {
  font-size: 1.05rem;
  color: var(--ink-soft);
  margin: 0;
}

/* A single quiet doorway under the intro. Same serif, accent colour
   (already established in the palette as the deep burgundy used for
   in-text links). No frame, no button, no animation — a placard line. */
.invitation {
  margin: 2rem 0 0;
  font-family: var(--serif);
  font-size: 1rem;
}

.invitation a {
  color: var(--accent);
}

.invitation a:hover {
  text-decoration: underline;
  text-underline-offset: 4px;
  text-decoration-thickness: 1px;
}

/* World page content (rendered from the world's index.md) */

.world-content {
  max-width: var(--measure);
}

.world-content > *:first-child { margin-top: 0; }

.world-content h1 {
  font-family: var(--serif);
  font-size: 2.25rem;
  line-height: 1.15;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0 0 1.5rem;
}

.world-content h2 {
  font-family: var(--serif);
  font-size: 1.3rem;
  font-weight: 600;
  margin: 2.75rem 0 0.75rem;
  letter-spacing: 0.002em;
}

.world-content h3 {
  font-family: var(--serif);
  font-size: 1.1rem;
  font-weight: 600;
  margin: 2rem 0 0.5rem;
}

.world-content p {
  font-size: 1.05rem;
  color: var(--ink-soft);
  margin: 0 0 1.25rem;
}

.world-content a {
  color: var(--accent);
}

.world-content code {
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.92em;
  background: rgba(0,0,0,0.04);
  padding: 0.08em 0.35em;
  border-radius: 2px;
}

/* Homepage world grid */

.world-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 42rem) {
  .world-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1.25rem;
  }
}

@media (min-width: 64rem) {
  .world-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* World card (reusable) */

.world-card {
  display: block;
  padding: 1.75rem 1.6rem;
  border: 1px solid var(--rule);
  background: transparent;
  transition: border-color 140ms ease, transform 140ms ease;
}

.world-card:hover,
.world-card:focus-visible {
  text-decoration: none;
  border-color: var(--ink);
  transform: translateY(-1px);
  outline: none;
}

.world-card__title {
  font-family: var(--serif);
  font-size: 1.4rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
  letter-spacing: 0.002em;
}

.world-card__summary {
  font-size: 0.97rem;
  color: var(--muted);
  margin: 0;
  line-height: 1.5;
}

/* Error / empty states */

.atlas-error {
  color: var(--muted);
  font-style: italic;
  max-width: var(--measure);
}

/* Footer (shell) */

.atlas-footer {
  border-top: 1px solid var(--rule);
  padding: 2.25rem var(--pad-x);
  text-align: center;
  font-family: var(--sans);
  font-size: 0.85rem;
  color: var(--muted);
}

.atlas-footer p { margin: 0; }

/* Small screens */

@media (max-width: 40rem) {
  .atlas-nav {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }
  .worlds-nav { gap: 1.25rem; flex-wrap: wrap; }
  .atlas-main { padding-top: 3rem; }
  .tagline { font-size: 1.8rem; }
}