/* ─────────────────────────────────────────────────────────────
   Interval Trainer — stylesheet
   Palette: warm off-white bg · dark ink · single accent (navy)
   Feedback states: forest green (correct) · deep red (incorrect)
───────────────────────────────────────────────────────────── */

:root {
  --bg:           #f6f6f3;
  --surface:      #ffffff;
  --border:       #deded8;
  --text:         #1a1a1a;
  --text-muted:   #666660;
  --accent:       #2b4b82;
  --accent-hover: #1e3660;
  --correct:      #2a6640;
  --correct-bg:   #edf7f1;
  --incorrect:    #9b2626;
  --incorrect-bg: #fdf0f0;
  --radius:       8px;
  --shadow:       0 1px 4px rgba(0,0,0,0.08);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  margin: 0;
  padding: 0 1rem 3rem;
  line-height: 1.5;
}

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

.site-header {
  text-align: center;
  padding: 2rem 0 1.25rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.site-header h1 {
  font-size: 1.4rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  margin: 0 0 0.25rem;
}

.subtitle {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin: 0;
  letter-spacing: 0.02em;
}

/* ── Layout ──────────────────────────────────────────────────── */

.main {
  max-width: 560px;
  margin: 0 auto;
}

/* ── Filters ─────────────────────────────────────────────────── */

.filters {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 0.6rem 0.75rem;
  margin-bottom: 1.25rem;
}

.filter-group {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.filter-group label {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text-muted);
}

.filter-group select {
  appearance: none;
  -webkit-appearance: none;
  background: var(--surface) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%23888'/%3E%3C/svg%3E") no-repeat right 0.6rem center / 8px 5px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.45rem 1.8rem 0.45rem 0.6rem;
  font-size: 0.85rem;
  color: var(--text);
  cursor: pointer;
  width: 100%;
}

.filter-group select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px rgba(43,75,130,0.15);
}

.filter-group select:disabled {
  opacity: 0.4;
  cursor: default;
}

/* ── Question card ───────────────────────────────────────────── */

.question-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow);
  padding: 1.5rem 1.25rem 1.25rem;
  margin-bottom: 1rem;
}

.question-prompt {
  font-size: 0.92rem;
  color: var(--text-muted);
  text-align: center;
  margin: 0 0 1.25rem;
  min-height: 1.4em;
}

.question-prompt strong {
  color: var(--text);
}

/* ── Stave ───────────────────────────────────────────────────── */

.stave-container {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 185px;
  margin-bottom: 1.25rem;
  /* overflow visible so ledger lines above/below the stave are never clipped */
  overflow: visible;
}

/* ── Answer buttons ──────────────────────────────────────────── */

.answers {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.5rem;
}

.answer-btn {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.65rem 0.75rem;
  font-size: 0.88rem;
  color: var(--text);
  cursor: pointer;
  text-align: center;
  transition: border-color 0.1s, background 0.1s;
  line-height: 1.3;
}

.answer-btn:hover:not(:disabled) {
  border-color: var(--accent);
  background: #eef2fb;
}

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

.answer-btn.correct {
  background: var(--correct-bg);
  border-color: var(--correct);
  color: var(--correct);
  font-weight: 600;
}

.answer-btn.incorrect {
  background: var(--incorrect-bg);
  border-color: var(--incorrect);
  color: var(--incorrect);
}

.answer-btn.reveal {
  background: var(--correct-bg);
  border-color: var(--correct);
  color: var(--correct);
  font-weight: 600;
}

/* ── Feedback ────────────────────────────────────────────────── */

.feedback {
  margin-top: 0.9rem;
  font-size: 0.83rem;
  line-height: 1.55;
  color: var(--text-muted);
  min-height: 1.2em;
  text-align: center;
}

.feedback.correct { color: var(--correct); }
.feedback.incorrect { color: var(--incorrect); }

/* ── Controls ────────────────────────────────────────────────── */

.controls {
  display: flex;
  gap: 0.6rem;
  justify-content: center;
  margin-bottom: 1.25rem;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  padding: 0.65rem 1.4rem;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.15s;
}

.btn-primary:hover { background: var(--accent-hover); }

.btn-secondary {
  background: var(--surface);
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  padding: 0.65rem 1.4rem;
  font-size: 0.9rem;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
}

.btn-secondary:hover {
  background: var(--accent);
  color: #fff;
}

/* ── Score panel ─────────────────────────────────────────────── */

.score-panel {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  padding: 0.9rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  flex-wrap: wrap;
}

.score-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.15rem;
}

.score-label {
  font-size: 0.68rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.score-value {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

.btn-ghost {
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.4rem 0.85rem;
  font-size: 0.78rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
}

.btn-ghost:hover {
  border-color: var(--incorrect);
  color: var(--incorrect);
}

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

@media (max-width: 420px) {
  .filters { grid-template-columns: 1fr 1fr; }
  .answers { grid-template-columns: 1fr; }
  .score-panel { gap: 1rem; }
}