/* ============================================================
   American Billboard Music — styles.css
   Dark theme, clean grid, mobile-first responsive
   ============================================================ */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg:          #0d0d0f;
  --bg-surface:  #17171b;
  --bg-elevated: #1f1f25;
  --bg-hover:    #27272f;
  --border:      #2a2a34;
  --accent:      #e8a838;
  --accent-dim:  #c48c28;
  --accent-glow: rgba(232, 168, 56, 0.15);
  --text-primary: #f0f0f2;
  --text-secondary: #9090a0;
  --text-muted:   #555565;
  --radius-sm:   6px;
  --radius-md:   12px;
  --radius-lg:   20px;
  --shadow-card: 0 2px 12px rgba(0,0,0,0.4);
  --shadow-glow: 0 0 24px rgba(232, 168, 56, 0.2);
  --font-body:   'Inter', system-ui, sans-serif;
  --font-display: 'DM Serif Display', Georgia, serif;
  --transition:  160ms ease;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  line-height: 1.6;
}

/* ── Header ───────────────────────────────────────────────── */

.site-header {
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo-icon {
  font-size: 1.5rem;
  color: var(--accent);
  line-height: 1;
}

.logo-text {
  font-family: var(--font-display);
  font-size: 1.25rem;
  letter-spacing: 0.01em;
  color: var(--text-primary);
}

.tagline {
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* ── Main ─────────────────────────────────────────────────── */

.main {
  flex: 1;
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  padding: 0 24px 64px;
}

/* ── Section labels ───────────────────────────────────────── */

.section-label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 16px;
}

/* ── Decade navigation ────────────────────────────────────── */

.decade-nav-section {
  padding: 36px 0 28px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 40px;
}

.decade-nav {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.decade-btn {
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 20px;
  cursor: pointer;
  transition: color var(--transition), background var(--transition),
              border-color var(--transition), box-shadow var(--transition);
}

.decade-btn:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
  border-color: #3a3a48;
}

.decade-btn.active {
  color: var(--accent);
  background: var(--accent-glow);
  border-color: var(--accent-dim);
  box-shadow: var(--shadow-glow);
}

/* ── Year section ─────────────────────────────────────────── */

.year-section {
  margin-bottom: 48px;
  animation: fadeIn 220ms ease;
}

.year-section-header {
  margin-bottom: 20px;
}

.year-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(88px, 1fr));
  gap: 10px;
}

.year-btn {
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 18px 8px;
  cursor: pointer;
  text-align: center;
  transition: color var(--transition), background var(--transition),
              border-color var(--transition), transform var(--transition),
              box-shadow var(--transition);
  letter-spacing: 0.02em;
}

.year-btn:hover {
  color: var(--text-primary);
  background: var(--bg-elevated);
  border-color: #3a3a48;
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.year-btn.active {
  color: var(--bg);
  background: var(--accent);
  border-color: var(--accent);
  box-shadow: var(--shadow-glow);
  transform: translateY(-2px);
}

/* ── Player section ───────────────────────────────────────── */

.player-section {
  animation: slideUp 240ms ease;
  margin-bottom: 48px;
}

.player-header {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.back-btn {
  font-family: var(--font-body);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 14px;
  cursor: pointer;
  transition: color var(--transition), border-color var(--transition);
  white-space: nowrap;
}

.back-btn:hover {
  color: var(--text-primary);
  border-color: var(--text-muted);
}

.player-title {
  font-family: var(--font-display);
  font-size: 1.6rem;
  color: var(--text-primary);
  font-weight: 400;
}

.player-container {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  min-height: 620px;
  display: flex;
  align-items: stretch;
}

.player-container iframe {
  display: block;
  border: none;
  flex: 1;
  min-height: 620px;
}

.player-placeholder {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding: 48px 24px;
  color: var(--text-muted);
  text-align: center;
}

.player-placeholder-icon {
  font-size: 3rem;
  opacity: 0.4;
}

.player-placeholder h3 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 400;
  color: var(--text-secondary);
}

.player-placeholder p {
  font-size: 0.85rem;
  max-width: 340px;
  line-height: 1.7;
}

.player-placeholder code {
  font-size: 0.8rem;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  color: var(--accent);
}

.player-note {
  margin-top: 12px;
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  text-align: center;
}

/* ── Hero ─────────────────────────────────────────────────── */

.hero {
  padding: 56px 0 0;
}

.hero-inner {
  text-align: center;
  max-width: 640px;
  margin: 0 auto;
}

.hero-headline {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 400;
  color: var(--text-primary);
  margin-bottom: 16px;
  line-height: 1.2;
}

.hero-sub {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 48px;
}

.hero-stats {
  display: flex;
  justify-content: center;
  gap: 48px;
  flex-wrap: wrap;
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.stat-num {
  font-family: var(--font-display);
  font-size: 2rem;
  color: var(--accent);
  line-height: 1;
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* ── Footer ───────────────────────────────────────────────── */

.site-footer {
  background: var(--bg-surface);
  border-top: 1px solid var(--border);
  text-align: center;
  padding: 20px 24px;
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.04em;
}

/* ── Animations ───────────────────────────────────────────── */

@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Responsive ───────────────────────────────────────────── */

@media (max-width: 640px) {
  .header-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
  }

  .tagline { display: none; }

  .decade-nav {
    gap: 6px;
  }

  .decade-btn {
    font-size: 0.82rem;
    padding: 8px 14px;
  }

  .year-grid {
    grid-template-columns: repeat(auto-fill, minmax(72px, 1fr));
    gap: 8px;
  }

  .year-btn {
    padding: 14px 6px;
    font-size: 0.92rem;
  }

  .hero-stats {
    gap: 32px;
  }

  .player-header {
    gap: 12px;
  }

  .player-title {
    font-size: 1.3rem;
  }
}

@media (max-width: 400px) {
  .main { padding: 0 16px 48px; }
  .decade-btn { padding: 8px 10px; font-size: 0.78rem; }
}