:root {
  color-scheme: light;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --secondary: #475569;
  --danger: #dc2626;
  --success: #15803d;
  --surface: #ffffff;
  --surface-muted: #f8fafc;
  --border: #dbe3ee;
  --text: #172033;
  --text-muted: #64748b;
  --shadow: 0 14px 35px rgb(15 23 42 / 8%);
  font-family: Inter, "Hiragino Sans", "Yu Gothic", Meiryo, sans-serif;
}

* { box-sizing: border-box; }
html { min-width: 320px; background: var(--surface-muted); }
body { margin: 0; color: var(--text); background: var(--surface-muted); line-height: 1.6; }
button, input { font: inherit; }
button { touch-action: manipulation; }
.hidden { display: none !important; }

.site-header { background: #172033; }
.site-nav { display: flex; max-width: 1180px; margin: auto; padding: 0 20px; overflow-x: auto; }
.site-nav a { flex: 0 0 auto; padding: 16px 20px 12px; color: #bdc9da; border-bottom: 4px solid transparent; font-weight: 700; text-decoration: none; }
.site-nav a:hover { color: #fff; }
.site-nav a[aria-current="page"] { color: #fff; border-bottom-color: #60a5fa; }

.app-shell { display: grid; grid-template-columns: 300px minmax(0, 1fr); min-height: calc(100vh - 58px); }
.settings { padding: 28px 24px; background: var(--surface); border-right: 1px solid var(--border); }
.settings h2 { margin: 0; font-size: 1rem; color: var(--primary); }
.settings-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 16px; }
.content { width: 100%; max-width: 900px; margin: 0 auto; padding: 44px clamp(20px, 5vw, 64px); }
h1 { margin: 0 0 12px; font-size: clamp(1.6rem, 3vw, 2.25rem); line-height: 1.3; }
.lead { margin: 0; color: var(--text-muted); }
.selection-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.type-selection { display: grid; gap: 10px; margin-top: 28px; }
.type-selection label { display: flex; align-items: center; gap: 8px; }
.category-button, .choice-button, .ghost-button, .primary-button, .secondary-button, .danger-button, .mode-button { border-radius: 10px; cursor: pointer; transition: .18s ease; }
.category-button { min-height: 46px; padding: 8px; border: 2px solid var(--border); background: #fff; color: var(--text); }
.category-button:hover { border-color: #93b4f5; }
.category-button.is-selected { border-color: var(--primary); background: var(--primary); color: #fff; font-weight: 700; }
.ghost-button { padding: 6px 10px; border: 1px solid var(--primary); background: transparent; color: var(--primary); font-size: .82rem; }
.primary-button, .secondary-button, .danger-button { min-height: 48px; padding: 11px 18px; border: 0; color: #fff; font-weight: 700; }
.primary-button { background: var(--primary); }
.primary-button:hover { background: var(--primary-dark); }
.secondary-button { background: var(--secondary); }
.danger-button { background: var(--danger); }
.actions { display: grid; gap: 10px; max-width: 420px; margin: 32px auto; }
.panel { padding: clamp(20px, 4vw, 34px); border: 1px solid var(--border); border-radius: 16px; background: var(--surface); box-shadow: var(--shadow); }
.question-meta { text-align: right; color: var(--text-muted); font-weight: 700; }
.question-title { margin: 20px 0; text-align: center; font-size: clamp(1.3rem, 3vw, 2rem); }
.choice-list { display: grid; gap: 10px; }
.choice-row { display: grid; grid-template-columns: 1fr auto; gap: 8px; }
.choice-button { width: 100%; padding: 14px; border: 2px solid var(--border); background: #fff; text-align: left; }
.choice-button:hover, .choice-button.is-selected { border-color: var(--primary); background: #eff6ff; }
.speaker-button { min-width: 48px; border: 1px solid var(--border); border-radius: 10px; background: #fff; cursor: pointer; }
.quiz-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 22px; }
.feedback { min-height: 38px; margin-top: 18px; text-align: center; font-size: 1.1rem; font-weight: 700; }
.correct { color: var(--success); }
.incorrect { color: var(--danger); }
.translation-input { width: 100%; padding: 14px; border: 2px solid var(--border); border-radius: 10px; }
.word-area { display: flex; flex-wrap: wrap; gap: 9px; min-height: 70px; padding: 14px; border: 2px dashed #aebdd0; border-radius: 10px; }
.word-bank { margin-top: 12px; background: #f1f5f9; }
.word-block { padding: 8px 12px; border: 1px solid var(--border); border-radius: 8px; background: #fff; cursor: pointer; }
.stats { margin-top: 44px; padding-top: 22px; border-top: 1px solid var(--border); }
.stats h2 { margin: 0 0 6px; font-size: 1rem; }
.credit { margin-top: 50px; padding-top: 18px; border-top: 1px solid var(--border); color: var(--text-muted); font-size: .8rem; text-align: center; }
.credit a { color: var(--primary); }
.result { text-align: center; }

@media (max-width: 760px) {
  .site-nav { padding: 0 8px; }
  .site-nav a { padding-inline: 12px; font-size: .9rem; }
  .app-shell { grid-template-columns: 1fr; }
  .settings { border-right: 0; border-bottom: 1px solid var(--border); }
  .content { padding-top: 30px; }
}