/* ============================================================
   カタカムナ 文字アーカイブ styles.css
   テーマ: 深紺 × 金（ゴールド）× 白
   ============================================================ */

:root {
  --bg:          #080a14;
  --surface:     #0f1220;
  --surface2:    #161929;
  --border:      #2a2f45;
  --gold:        #c8a86a;
  --gold-bright: #e0c080;
  --gold-dim:    #8a7048;
  --text:        #e8e4d8;
  --muted:       #7a7a8a;
  --radius:      10px;
  --spiral-color: #c8a86a;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Hiragino Kaku Gothic ProN', 'Noto Sans JP', sans-serif;
  line-height: 1.7;
  min-height: 100vh;
}

/* ── Header ───────────────────────────────────── */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 2rem;
  background: rgba(8,10,20,0.95);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--gold);
  font-weight: 700;
  font-size: 1rem;
  letter-spacing: 0.04em;
}
.brand-mark {
  font-size: 1.2rem;
  color: var(--gold-bright);
}

.site-nav {
  display: flex;
  gap: 1.2rem;
  align-items: center;
}
.site-nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.85rem;
  transition: color 0.2s;
}
.site-nav a:hover { color: var(--text); }
.nav-back { opacity: 0.7; font-size: 0.82rem; }

/* ── Viewer Section ───────────────────────────── */
.viewer-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 2rem 1rem 3rem;
  background: radial-gradient(ellipse at center, #111525 0%, var(--bg) 70%);
  min-height: 90vh;
}

/* Song Navigation */
.song-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-bottom: 1.5rem;
  width: 100%;
  max-width: 480px;
}

.nav-btn {
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--gold);
  width: 44px;
  height: 44px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1rem;
  transition: background 0.15s, transform 0.1s;
  flex-shrink: 0;
}
.nav-btn:hover { background: var(--border); transform: scale(1.05); }
.nav-btn:active { transform: scale(0.95); }

.song-nav-center {
  flex: 1;
  text-align: center;
}
.nav-number {
  display: block;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--gold-bright);
  letter-spacing: 0.06em;
  font-variant-numeric: tabular-nums;
}
.nav-group {
  display: block;
  font-size: 0.8rem;
  color: var(--muted);
  margin-top: 0.1rem;
}

/* Song Image Viewer */
.song-viewer {
  width: min(380px, 88vw);
  background: var(--bg);
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 0 32px rgba(200, 168, 106, 0.12);
}

.song-img {
  width: 100%;
  display: block;
  filter: invert(1) sepia(0.2) saturate(1.2) hue-rotate(5deg);
  transition: opacity 0.2s;
}

/* Info Panel */
.info-panel {
  width: 100%;
  max-width: 540px;
  margin-top: 1.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.info-top {
  padding: 1.2rem 1.4rem 0.8rem;
}

.info-utahi {
  font-size: 1.05rem;
  color: var(--gold-bright);
  font-weight: 600;
  letter-spacing: 0.08em;
  line-height: 1.8;
  margin-bottom: 0.5rem;
}

.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 0.4rem;
}

.badge-verified {
  background: rgba(50,180,100,0.15);
  border: 1px solid rgba(50,180,100,0.4);
  color: #5dba82;
  font-size: 0.72rem;
  padding: 0.15rem 0.6rem;
  border-radius: 4px;
}
.badge-inferred {
  background: rgba(200,168,106,0.12);
  border: 1px solid rgba(200,168,106,0.3);
  color: var(--gold);
  font-size: 0.72rem;
  padding: 0.15rem 0.6rem;
  border-radius: 4px;
}

/* Accordion */
.accordion-toggle {
  width: 100%;
  background: var(--surface2);
  border: none;
  border-top: 1px solid var(--border);
  color: var(--muted);
  padding: 0.75rem 1.4rem;
  cursor: pointer;
  font-size: 0.9rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background 0.15s, color 0.15s;
}
.accordion-toggle:hover { background: var(--border); color: var(--text); }
.accordion-toggle[aria-expanded="true"] { color: var(--gold); }
.accordion-toggle[aria-expanded="true"] .toggle-icon { transform: rotate(180deg); }
.toggle-icon { transition: transform 0.2s; display: inline-block; }

.accordion-body {
  padding: 1rem 1.4rem 1.2rem;
  border-top: 1px solid var(--border);
}
.info-summary {
  font-size: 0.92rem;
  color: var(--text);
  margin-bottom: 0.8rem;
}
.info-interp {
  font-size: 0.88rem;
  color: var(--muted);
  line-height: 1.85;
}

/* ── Index Section ────────────────────────────── */
.index-section {
  padding: 3rem 1.5rem;
  background: var(--surface);
}

.section-inner { max-width: 900px; margin: 0 auto; }

.section-heading { margin-bottom: 1.5rem; }
.section-heading.compact { margin-bottom: 1.2rem; }

.eyebrow {
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gold-dim);
  margin-bottom: 0.3rem;
}

.section-heading h2 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--gold-bright);
  margin-bottom: 0.4rem;
}
.section-heading p {
  font-size: 0.9rem;
  color: var(--muted);
  max-width: 580px;
}

/* Segmented control */
.segmented {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1.2rem;
}
.segment {
  background: var(--surface2);
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 0.35rem 0.85rem;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.82rem;
  transition: all 0.15s;
}
.segment:hover { border-color: var(--gold-dim); color: var(--text); }
.segment.active {
  background: rgba(200,168,106,0.15);
  border-color: var(--gold);
  color: var(--gold-bright);
  font-weight: 600;
}

/* Index Grid */
.index-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(70px, 1fr));
  gap: 0.5rem;
}

.index-cell {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.5rem 0.3rem;
  text-align: center;
  cursor: pointer;
  transition: all 0.15s;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.3rem;
}
.index-cell:hover {
  border-color: var(--gold-dim);
  background: rgba(200,168,106,0.07);
}
.index-cell.active {
  border-color: var(--gold);
  background: rgba(200,168,106,0.15);
}
.index-cell.filtered-out { opacity: 0.25; pointer-events: none; }

.index-cell-num {
  font-size: 0.65rem;
  color: var(--muted);
}
.index-cell-img {
  width: 48px;
  height: 60px;
  overflow: hidden;
  border-radius: 4px;
}
.index-cell-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 50% 30%;
  filter: invert(1) sepia(0.2) saturate(1.2) hue-rotate(5deg);
  display: block;
}

/* ── Character Reference Section ──────────────── */
.char-section {
  padding: 3rem 1.5rem;
  background: var(--bg);
}

.char-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
  gap: 0.6rem;
}

.char-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.7rem 0.4rem 0.5rem;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
  transition: border-color 0.15s;
}
.char-card:hover { border-color: var(--gold-dim); }

.char-svg {
  width: 44px;
  height: 44px;
}
.char-svg svg {
  width: 100%;
  height: 100%;
  color: var(--gold);
}
.char-label {
  font-size: 1rem;
  font-weight: 700;
  color: var(--gold-bright);
}
.char-romaji {
  font-size: 0.65rem;
  color: var(--muted);
  text-transform: uppercase;
}

/* ── Footer ───────────────────────────────────── */
.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 1.5rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}
.site-footer strong { color: var(--gold); }
.site-footer p { font-size: 0.8rem; color: var(--muted); }
.footer-links {
  display: flex;
  gap: 1.2rem;
  flex-wrap: wrap;
}
.footer-links a {
  color: var(--muted);
  font-size: 0.85rem;
  text-decoration: none;
  transition: color 0.15s;
}
.footer-links a:hover { color: var(--text); }

/* ── Responsive ───────────────────────────────── */
@media (max-width: 600px) {
  .site-header { padding: 0.6rem 1rem; }
  .site-nav { gap: 0.8rem; }
  .viewer-section { padding: 1.2rem 0.8rem 2rem; }
  .song-viewer { width: min(340px, 94vw); }
  .index-grid { grid-template-columns: repeat(auto-fill, minmax(56px, 1fr)); }
  .char-grid { grid-template-columns: repeat(auto-fill, minmax(66px, 1fr)); }
  .site-footer { flex-direction: column; align-items: flex-start; }
}

/* ── Composite-character Note ─────────────────── */
.composite-note {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  max-width: 640px;
  margin: 0 auto 2rem;
  padding: 0.9rem 1.2rem;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-left: 3px solid var(--gold);
  border-radius: 6px;
  font-size: 0.82rem;
  color: var(--muted);
  line-height: 1.7;
}
.composite-note-icon {
  flex-shrink: 0;
  font-size: 1.1rem;
  color: var(--gold);
  margin-top: 0.05rem;
}
.composite-note p { margin: 0; }

/* ── Animations ───────────────────────────────── */
@keyframes fadeIn {
  from { opacity: 0; transform: scale(0.96); }
  to   { opacity: 1; transform: scale(1); }
}
.spiral-appear {
  animation: fadeIn 0.35s ease-out;
}