:root {
  --bg: #f7f4ef;
  --surface: #ffffff;
  --text: #1a1a2e;
  --text-muted: #6b7280;
  --accent: #c73e3a;
  --accent-soft: #fde8e7;
  --border: #e8e4dc;
  --shadow: 0 2px 12px rgba(26, 26, 46, 0.08);
  --radius: 12px;
  --font-kana: "Hiragino Sans", "Yu Gothic UI", "Meiryo", "Noto Sans JP", sans-serif;
}

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

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}

/* ── Header & Nav ── */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0 1.5rem;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow);
}

.site-header-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  gap: 1rem;
}

.logo {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--accent);
  text-decoration: none;
  white-space: nowrap;
}

.logo span {
  color: var(--text);
  font-weight: 400;
}

nav {
  display: flex;
  gap: 0.25rem;
  flex-wrap: wrap;
  justify-content: flex-end;
}

nav a {
  padding: 0.45rem 1rem;
  border-radius: 8px;
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: background 0.15s, color 0.15s;
}

nav a:hover {
  background: var(--accent-soft);
  color: var(--accent);
}

nav a.active {
  background: var(--accent);
  color: #fff;
}

/* ── Main ── */
main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
}

.page-title {
  margin: 0 0 0.35rem;
  font-size: 1.75rem;
  font-weight: 700;
}

.page-desc {
  margin: 0 0 2rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* ── Chart sections ── */
.chart-section {
  margin-bottom: 2.5rem;
}

.section-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 0 0 1rem;
  padding-left: 0.75rem;
  border-left: 4px solid var(--accent);
}

/* ── Kana table ── */
.kana-table-wrap {
  overflow-x: auto;
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

.kana-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 520px;
}

.kana-table th,
.kana-table td {
  text-align: center;
  padding: 0.6rem 0.5rem;
  border: 1px solid var(--border);
}

.kana-table thead th {
  background: #faf8f5;
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.kana-table .row-label {
  background: #faf8f5;
  font-family: var(--font-kana);
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent);
  white-space: nowrap;
  width: 72px;
}

.kana-cell {
  min-width: 88px;
  transition: background 0.15s;
}

.kana-cell:hover {
  background: var(--accent-soft);
}

.kana-cell.empty {
  background: #fafafa;
}

.kana-hiragana {
  font-family: var(--font-kana);
  font-size: 1.6rem;
  line-height: 1.2;
  display: block;
}

.kana-katakana {
  font-family: var(--font-kana);
  font-size: 1.25rem;
  color: #4b5563;
  display: block;
  margin-top: 0.15rem;
}

.kana-romaji {
  font-size: 0.75rem;
  color: var(--text-muted);
  display: block;
  margin-top: 0.2rem;
  letter-spacing: 0.03em;
}

/* ── Practice page controls ── */
.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
  margin-bottom: 1.75rem;
  padding: 1.25rem;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.control-group label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.display-modes {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.mode-btn {
  padding: 0.4rem 0.85rem;
  border: 2px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  cursor: pointer;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text);
  transition: all 0.15s;
}

.mode-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.mode-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.filter-group {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.filter-btn {
  padding: 0.35rem 0.75rem;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: transparent;
  cursor: pointer;
  font-size: 0.82rem;
  color: var(--text-muted);
  transition: all 0.15s;
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
}

.btn-shuffle {
  margin-left: auto;
  padding: 0.55rem 1.25rem;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.15s, transform 0.1s;
  white-space: nowrap;
}

.btn-shuffle:hover {
  opacity: 0.9;
}

.btn-shuffle:active {
  transform: scale(0.97);
}

.count-badge {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ── Practice grid ── */
.practice-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
  gap: 0.75rem;
}

.practice-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem 0.5rem;
  text-align: center;
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s, border-color 0.15s;
  min-height: 100px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  user-select: none;
}

.practice-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(26, 26, 46, 0.12);
}

.practice-card.revealed {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.practice-card .show-hiragana,
.practice-card .show-katakana,
.practice-card .show-romaji {
  display: block;
  line-height: 1.2;
}

.practice-card.modes-1 .show-hiragana,
.practice-card.modes-1 .show-katakana {
  font-family: var(--font-kana);
  font-size: 2rem;
}

.practice-card.modes-1 .show-romaji {
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.04em;
}

.practice-card.modes-2 .show-hiragana,
.practice-card.modes-2 .show-katakana {
  font-family: var(--font-kana);
  font-size: 1.5rem;
}

.practice-card.modes-2 .show-romaji {
  font-size: 1rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.04em;
  margin-top: 0.15rem;
}

.practice-card.modes-3 .show-hiragana {
  font-family: var(--font-kana);
  font-size: 1.4rem;
}

.practice-card.modes-3 .show-katakana {
  font-family: var(--font-kana);
  font-size: 1.15rem;
  color: #4b5563;
  margin-top: 0.1rem;
}

.practice-card.modes-3 .show-romaji {
  font-size: 0.8rem;
  color: var(--text-muted);
  letter-spacing: 0.03em;
  margin-top: 0.15rem;
}

/* ── Reaction page ── */
.reaction-setup {
  align-items: flex-end;
}

.btn-start {
  margin-left: auto;
  padding: 0.7rem 2rem;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 10px;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: opacity 0.15s, transform 0.1s;
  white-space: nowrap;
}

.btn-start:hover {
  opacity: 0.9;
}

.btn-start:active {
  transform: scale(0.97);
}

.btn-stop {
  margin-left: auto;
  padding: 0.35rem 0.85rem;
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.82rem;
  cursor: pointer;
}

.btn-stop:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.reaction-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
  margin-bottom: 1.5rem;
  padding: 1rem 1.25rem;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 64px;
}

.stat-val {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1.2;
}

.stat-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  margin-top: 0.15rem;
}

.voice-hint {
  margin: 0;
  font-size: 0.8rem;
  color: var(--text-muted);
  flex: 1;
  min-width: 180px;
}

.listen-area {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 0.5rem;
  min-height: 8rem;
  justify-content: center;
}

.btn-listen {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  border: 3px solid var(--accent);
  background: var(--accent-soft);
  font-size: 2.5rem;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

.btn-listen:hover {
  transform: scale(1.05);
  box-shadow: 0 6px 20px rgba(199, 62, 58, 0.25);
}

.btn-listen:active {
  transform: scale(0.97);
}

.btn-replay {
  padding: 0.35rem 1rem;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--surface);
  color: var(--text-muted);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.15s;
}

.btn-replay:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
}

.reaction-arena {
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  padding: 2rem 1.5rem;
  text-align: center;
}

.question-hint {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.question-display {
  min-height: 5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 0.5rem;
}

.question-display.fmt-hiragana,
.question-display.fmt-katakana {
  font-family: var(--font-kana);
  font-size: 4.5rem;
  line-height: 1;
}

.question-display.fmt-romaji {
  font-size: 3rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.06em;
}

.reaction-timer {
  font-size: 0.95rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  margin-bottom: 1.75rem;
  transition: color 0.2s;
}

.reaction-timer.slow {
  color: var(--accent);
  font-weight: 600;
}

.answer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  max-width: 480px;
  margin: 0 auto;
}

.answer-btn {
  padding: 1.1rem 0.5rem;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  background: #faf8f5;
  cursor: pointer;
  transition: all 0.15s;
  font-weight: 500;
}

.answer-btn.fmt-hiragana,
.answer-btn.fmt-katakana {
  font-family: var(--font-kana);
  font-size: 1.75rem;
}

.answer-btn.fmt-romaji {
  font-size: 1.2rem;
  letter-spacing: 0.04em;
}

.answer-btn:hover:not(:disabled) {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.answer-btn:disabled {
  cursor: default;
}

.answer-btn.is-correct {
  border-color: #16a34a;
  background: #dcfce7;
  color: #15803d;
}

.answer-btn.is-wrong {
  border-color: var(--accent);
  background: var(--accent-soft);
}

[hidden] {
  display: none !important;
}

.countdown-overlay,
.feedback-overlay {
  position: fixed;
  inset: 0;
  background: rgba(26, 26, 46, 0.55);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 200;
  pointer-events: none;
}

.countdown-overlay.is-open,
.feedback-overlay.is-open,
.report-overlay.is-open {
  display: flex;
  pointer-events: auto;
}

.report-overlay {
  position: fixed;
  inset: 0;
  background: rgba(26, 26, 46, 0.6);
  display: none;
  align-items: flex-start;
  justify-content: center;
  z-index: 300;
  pointer-events: none;
  padding: 1.5rem;
  overflow-y: auto;
}

.report-panel {
  background: var(--surface);
  border-radius: 16px;
  width: min(720px, 100%);
  padding: 1.75rem;
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.2);
  margin: auto 0;
}

.report-header h2 {
  margin: 0 0 0.35rem;
  font-size: 1.5rem;
}

.report-sub {
  margin: 0 0 1.25rem;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.report-summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(90px, 1fr));
  gap: 0.65rem;
  margin-bottom: 1rem;
}

.report-metric {
  background: #faf8f5;
  border-radius: 10px;
  padding: 0.75rem 0.5rem;
  text-align: center;
}

.rm-val {
  display: block;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--accent);
}

.rm-label {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.report-formula {
  font-size: 0.82rem;
  color: var(--text-muted);
  background: var(--accent-soft);
  padding: 0.65rem 0.85rem;
  border-radius: 8px;
  margin-bottom: 1.25rem;
}

.report-distribution {
  margin-bottom: 1.5rem;
}

.report-distribution h3 {
  margin: 0 0 0.75rem;
  font-size: 1rem;
}

.dist-row {
  display: grid;
  grid-template-columns: 110px 1fr 72px;
  gap: 0.5rem;
  align-items: center;
  margin-bottom: 0.45rem;
  font-size: 0.82rem;
}

.dist-label {
  white-space: nowrap;
}

.dist-bar-wrap {
  height: 10px;
  background: #eee;
  border-radius: 5px;
  overflow: hidden;
}

.dist-bar {
  height: 100%;
  border-radius: 5px;
  min-width: 2px;
}

.dist-bar.tier-mastered { background: #16a34a; }
.dist-bar.tier-good { background: #3b82f6; }
.dist-bar.tier-practice { background: #f59e0b; }
.dist-bar.tier-weak { background: var(--accent); }
.dist-bar.tier-unseen { background: #d1d5db; }

.dist-val {
  text-align: right;
  color: var(--text-muted);
  font-size: 0.78rem;
}

.report-tier {
  margin-bottom: 1.25rem;
  padding-top: 0.5rem;
  border-top: 1px solid var(--border);
}

.report-tier h3 {
  margin: 0 0 0.25rem;
  font-size: 1rem;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.tier-count {
  margin-left: auto;
  font-size: 0.82rem;
  color: var(--text-muted);
  font-weight: 500;
}

.tier-desc {
  margin: 0 0 0.65rem;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.report-kana-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.report-kana {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  padding: 0.45rem 0.65rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #faf8f5;
  min-width: 64px;
  cursor: default;
}

.report-kana .rk-icon {
  font-size: 0.9rem;
  line-height: 1;
}

.report-kana .rk-main {
  font-family: var(--font-kana);
  font-size: 1.25rem;
  line-height: 1.2;
}

.report-kana .rk-sub {
  font-size: 0.68rem;
  color: var(--text-muted);
}

.report-kana.tier-mastered { border-color: #86efac; background: #f0fdf4; }
.report-kana.tier-good { border-color: #93c5fd; background: #eff6ff; }
.report-kana.tier-practice { border-color: #fcd34d; background: #fffbeb; }
.report-kana.tier-weak { border-color: #fca5a5; background: var(--accent-soft); }
.report-kana.tier-unseen { opacity: 0.75; }

.report-actions {
  margin-top: 1.5rem;
  text-align: center;
}

.report-actions .btn-start {
  margin-left: 0;
}

.countdown-num {
  font-size: 6rem;
  font-weight: 800;
  color: #fff;
  text-shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
}

.countdown-num.pop {
  animation: countdown-pop 0.5s ease-out;
}

@keyframes countdown-pop {
  0% { transform: scale(0.5); opacity: 0; }
  60% { transform: scale(1.15); opacity: 1; }
  100% { transform: scale(1); }
}

.feedback-card {
  background: var(--surface);
  border-radius: 16px;
  padding: 2rem 2.5rem;
  text-align: center;
  min-width: 260px;
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.2);
}

.feedback-card.correct .feedback-result {
  color: #16a34a;
}

.feedback-card.wrong .feedback-result {
  color: var(--accent);
}

.feedback-result {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.35rem;
}

.feedback-time {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.feedback-detail {
  font-size: 0.88rem;
  color: var(--text-muted);
}

/* ── Responsive ── */
@media (max-width: 600px) {
  .site-header-inner {
    flex-direction: column;
    height: auto;
    padding: 0.75rem 0;
  }

  nav {
    width: 100%;
    justify-content: center;
    gap: 0.15rem;
  }

  nav a {
    padding: 0.4rem 0.55rem;
    font-size: 0.78rem;
  }

  .controls {
    flex-direction: column;
    align-items: stretch;
  }

  .btn-shuffle {
    margin-left: 0;
    width: 100%;
  }

  .kana-hiragana {
    font-size: 1.35rem;
  }

  .kana-katakana {
    font-size: 1.05rem;
  }

  .question-display.fmt-hiragana,
  .question-display.fmt-katakana {
    font-size: 3.2rem;
  }

  .question-display.fmt-romaji {
    font-size: 2.2rem;
  }

  .reaction-setup {
    flex-direction: column;
    align-items: stretch;
  }

  .btn-start {
    margin-left: 0;
    width: 100%;
  }
}