/* ============================================================
   components.css — Nav, cards, breadcrumb, prev/next, buttons
   How Physics Works — v1.0
   ============================================================ */

/* ── Era Timeline Bar ───────────────────────────────────────── */
.era-timeline {
  display: flex;
  gap: 2px;
  width: 100%;
  border-radius: var(--radius-md);
  overflow: hidden;
  margin-block: var(--space-12);
}

.era-timeline__item {
  flex: 1;
  padding: var(--space-4) var(--space-3);
  cursor: pointer;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
  text-align: center;
  background: var(--era-bg, var(--color-surface));
  border-bottom: 3px solid var(--era-color, var(--color-gold));
  min-width: 0;
}

.era-timeline__item:hover { opacity: 0.85; transform: translateY(-2px); }

.era-timeline__item[data-era="ancient"]        { --era-color: var(--era-ancient-color);      --era-bg: var(--era-ancient-bg); }
.era-timeline__item[data-era="revolution"]     { --era-color: var(--era-revolution-color);   --era-bg: var(--era-revolution-bg); }
.era-timeline__item[data-era="classical"]      { --era-color: var(--era-classical-color);    --era-bg: var(--era-classical-bg); }
.era-timeline__item[data-era="modern"]         { --era-color: var(--era-modern-color);       --era-bg: var(--era-modern-bg); }
.era-timeline__item[data-era="contemporary"]   { --era-color: var(--era-contemporary-color); --era-bg: var(--era-contemporary-bg); }

.era-timeline__label {
  font-family: var(--font-display);
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--era-color);
  display: block;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.era-timeline__dates {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  display: block;
  margin-top: var(--space-1);
}

/* ── Era Section ────────────────────────────────────────────── */
.era-section {
  margin-block: var(--space-16);
  scroll-margin-top: 80px;
}

.era-section__header {
  display: flex;
  align-items: baseline;
  gap: var(--space-4);
  margin-bottom: var(--space-8);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid oklch(1 0 0 / 0.08);
}

.era-section__name {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  color: var(--era-color);
}

.era-section[data-era="ancient"]        .era-section__name { color: var(--era-ancient-color); }
.era-section[data-era="revolution"]     .era-section__name { color: var(--era-revolution-color); }
.era-section[data-era="classical"]      .era-section__name { color: var(--era-classical-color); }
.era-section[data-era="modern"]         .era-section__name { color: var(--era-modern-color); }
.era-section[data-era="contemporary"]   .era-section__name { color: var(--era-contemporary-color); }

.era-section__tagline {
  font-style: italic;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

.era-section__description {
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  margin-bottom: var(--space-6);
  max-width: 60ch;
}

/* ── Stop Card Grid ─────────────────────────────────────────── */
.stop-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: var(--space-4);
}

/* ── Stop Card ──────────────────────────────────────────────── */
.stop-card {
  display: block;
  position: relative;
  background: var(--color-deep);
  border: 1px solid oklch(1 0 0 / 0.07);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  text-decoration: none;
  color: inherit;
  transition: transform var(--transition-base), border-color var(--transition-base), box-shadow var(--transition-base);
  overflow: hidden;
}

.stop-card::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(135deg, var(--era-card-color, var(--color-gold)) 0%, transparent 60%);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.stop-card:hover {
  transform: translateY(-3px);
  border-color: var(--era-card-color, var(--color-gold));
  box-shadow: 0 8px 24px oklch(0 0 0 / 0.5), 0 0 0 1px var(--era-card-color, var(--color-gold)) inset;
}

.stop-card:hover::before { opacity: 0.04; }

.stop-card[data-era="ancient"]        { --era-card-color: var(--era-ancient-color); }
.stop-card[data-era="revolution"]     { --era-card-color: var(--era-revolution-color); }
.stop-card[data-era="classical"]      { --era-card-color: var(--era-classical-color); }
.stop-card[data-era="modern"]         { --era-card-color: var(--era-modern-color); }
.stop-card[data-era="contemporary"]   { --era-card-color: var(--era-contemporary-color); }

.stop-card__number {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--era-card-color, var(--color-gold));
  letter-spacing: 0.1em;
  margin-bottom: var(--space-2);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.stop-card__number::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--era-card-color, var(--color-gold));
  opacity: 0.3;
}

.stop-card__title {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text-primary);
  line-height: 1.3;
  margin-bottom: var(--space-1);
}

.stop-card__subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  font-style: italic;
  margin-bottom: var(--space-3);
  line-height: 1.4;
}

.stop-card__meta {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}

.stop-card__year {
  font-family: var(--font-mono);
}

.stop-card__scientist {
  color: var(--era-card-color, var(--color-gold));
  opacity: 0.85;
}

.stop-card__visited-badge {
  position: absolute;
  top: var(--space-3);
  right: var(--space-3);
  display: none;
  align-items: center;
  gap: 4px;
  font-family: var(--font-body);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--color-gold);
  background: oklch(0.72 0.12 60 / 0.15);
  border: 1px solid oklch(0.72 0.12 60 / 0.4);
  border-radius: 999px;
  padding: 2px 8px 2px 6px;
  line-height: 1;
}

.stop-card__visited-badge::before {
  content: '✓';
  font-size: 9px;
}

.stop-card.is-visited .stop-card__visited-badge { display: flex; }

.stop-card.is-visited {
  border-color: oklch(0.72 0.12 60 / 0.35);
  box-shadow: 0 0 0 1px oklch(0.72 0.12 60 / 0.2) inset;
}

.stop-card--stub {
  /* Stub cards are fully interactive — opacity and pointer-events removed */
  cursor: pointer;
}

.stop-card--stub::after {
  content: 'Coming Soon';
  position: absolute;
  top: var(--space-3);
  right: var(--space-3);
  font-size: 0.65rem;
  color: var(--color-text-muted);
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background: oklch(1 0 0 / 0.06);
  border: 1px solid oklch(1 0 0 / 0.12);
  border-radius: 999px;
  padding: 2px 8px;
  line-height: 1.6;
}

/* ── Breadcrumb ─────────────────────────────────────────────── */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-8);
  flex-wrap: wrap;
}

.breadcrumb__item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.breadcrumb__item:not(:last-child)::after {
  content: '/';
  color: var(--color-text-muted);
  opacity: 0.5;
}

.breadcrumb__link {
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

.breadcrumb__link:hover { color: var(--color-gold); }

.breadcrumb__current {
  color: var(--era-card-color, var(--color-gold));
  font-weight: 500;
}

/* ── Stop Navigation (Prev/Next) ────────────────────────────── */
.stop-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  margin-top: var(--space-16);
  padding-top: var(--space-8);
  border-top: 1px solid oklch(1 0 0 / 0.08);
}

.stop-nav__btn {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  padding: var(--space-4) var(--space-5);
  background: var(--color-deep);
  border: 1px solid oklch(1 0 0 / 0.07);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: inherit;
  transition: border-color var(--transition-base), transform var(--transition-base);
}

.stop-nav__btn--next { text-align: right; }

.stop-nav__btn:hover {
  border-color: var(--color-gold);
  transform: translateY(-2px);
}

.stop-nav__direction {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-family: var(--font-mono);
}

.stop-nav__title {
  font-family: var(--font-display);
  font-size: var(--text-md);
  color: var(--color-text-primary);
  line-height: 1.3;
}

/* .stop-nav__empty: intentional empty cell for grid alignment */

/* ── Buttons ────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-5);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: 0.02em;
  transition: all var(--transition-fast);
  min-height: 44px;
  min-width: 44px;
}

.btn-primary {
  background: var(--color-gold);
  color: oklch(0.1 0.02 82);
}
.btn-primary:hover { background: oklch(0.86 0.17 82); }

.btn-secondary {
  background: var(--color-surface);
  color: var(--color-text-primary);
  border: 1px solid oklch(1 0 0 / 0.12);
}
.btn-secondary:hover { border-color: var(--color-gold); color: var(--color-gold); }

.btn-ghost {
  color: var(--color-text-secondary);
  border: 1px solid transparent;
}
.btn-ghost:hover { border-color: oklch(1 0 0 / 0.12); color: var(--color-text-primary); }

/* ── Progress Bar ───────────────────────────────────────────── */
.progress-bar {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.progress-bar__track {
  flex: 1;
  height: 3px;
  background: oklch(1 0 0 / 0.1);
  border-radius: 999px;
  overflow: hidden;
}

.progress-bar__fill {
  height: 100%;
  background: var(--color-gold);
  border-radius: 999px;
  transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ── Landing Hero ───────────────────────────────────────────── */
.hero {
  padding-block: var(--space-20) var(--space-12);
  text-align: center;
  position: relative;
}

.hero__eyebrow {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--color-gold);
  margin-bottom: var(--space-4);
}

.hero__title {
  font-size: var(--text-4xl);
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-5);
  background: linear-gradient(135deg, var(--color-text-primary) 0%, oklch(0.75 0.05 90) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  max-width: 52ch;
  margin-inline: auto;
  margin-bottom: var(--space-8);
  line-height: 1.6;
}

.hero__stats {
  display: flex;
  justify-content: center;
  gap: var(--space-8);
  flex-wrap: wrap;
}

.hero__stat {
  text-align: center;
}

.hero__stat-number {
  font-family: var(--font-display);
  font-size: var(--text-3xl);
  font-weight: 700;
  color: var(--color-gold);
  display: block;
  line-height: 1;
}

.hero__stat-label {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-top: var(--space-1);
  display: block;
}

/* ── Decorative Star Field ──────────────────────────────────── */
.star-field {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.star-field__canvas {
  width: 100%;
  height: 100%;
}

.page-content {
  position: relative;
  z-index: 1;
}