:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #14141f;
  --bg-tertiary: #1e1e2e;
  --text-primary: #ffffff;
  --text-secondary: #a0a0b0;
  --text-muted: #606070;
  --accent: #00d4ff;
  --accent-secondary: #00ff88;
  --danger: #ff4466;
  --focus-ring: #00d4ff;
  --focus-glow: rgba(0, 212, 255, 0.4);
  --radius-md: 12px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html, body {
  width: 600px; height: 600px; overflow: hidden;
  background: #000;
  color: var(--text-primary);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}
#app { width: 100%; height: 100%; position: relative; }
.screen { width: 100%; height: 100%; position: absolute; top: 0; left: 0; display: flex; flex-direction: column; }
.screen.hidden { display: none; }
.focusable { transition: all 0.15s ease; border: 2px solid transparent; cursor: pointer; outline: none; }
.focusable:focus { border-color: var(--focus-ring); box-shadow: 0 0 20px var(--focus-glow); }
.hidden { display: none !important; }

/* ---------- Header ---------- */
.hdr {
  padding: 18px 20px 12px;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--bg-tertiary);
}
.hdr h1 { font-size: 30px; font-weight: 700; letter-spacing: -0.5px; }
.hdr .sub { font-size: 15px; color: var(--text-secondary); margin-top: 2px; }
.hdr-scale h1 { color: var(--accent); }

/* ---------- Home ---------- */
.home-body { flex: 1; display: flex; flex-direction: column; padding: 14px 20px 18px; gap: 14px; }
.block-label {
  font-size: 13px; text-transform: uppercase; letter-spacing: 1px;
  color: var(--text-muted); margin-bottom: 8px;
}
.root-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; }
.scale-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px; }

.pick {
  min-height: 46px;
  display: flex; align-items: center; justify-content: center;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-radius: var(--radius-md);
  font-size: 20px; font-weight: 600;
}
.scale-grid .pick { font-size: 16px; min-height: 50px; }
.pick.selected {
  background: var(--bg-tertiary);
  border-color: var(--accent-secondary);
  color: var(--accent-secondary);
  box-shadow: inset 0 0 0 1px var(--accent-secondary);
}
.pick.selected:focus { border-color: var(--focus-ring); }

.home-actions { margin-top: auto; display: flex; gap: 10px; }

/* ---------- Buttons ---------- */
.btn {
  flex: 1;
  min-height: 60px;
  display: flex; align-items: center; justify-content: center;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border-radius: var(--radius-md);
  font-size: 18px; font-weight: 600;
}
.btn-primary { background: var(--bg-tertiary); color: var(--accent); }
.btn-ghost { background: var(--bg-secondary); color: var(--text-secondary); }

/* ---------- Scale display ---------- */
.scale-body { flex: 1; display: flex; flex-direction: column; justify-content: center; padding: 10px 14px; gap: 16px; }
.notes-row { display: grid; grid-template-columns: repeat(8, 1fr); gap: 6px; }
.note {
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  padding: 12px 2px 10px;
  text-align: center;
  border: 2px solid transparent;
}
.note .deg { font-size: 12px; color: var(--text-muted); margin-bottom: 4px; }
.note .nm { font-size: 26px; font-weight: 700; line-height: 1; }
.note.tonic { border-color: var(--accent); }
.note.tonic .nm { color: var(--accent); }
.note.octave .nm { color: var(--accent-secondary); }

.steps {
  display: flex; justify-content: center; align-items: center;
  gap: 6px; flex-wrap: wrap;
}
.step-tok {
  font-size: 14px; font-weight: 600; color: var(--text-secondary);
  background: var(--bg-secondary); border-radius: 8px; padding: 4px 9px;
}
.step-tok.aug { color: var(--danger); }
.legend { text-align: center; font-size: 13px; color: var(--text-muted); }

.scale-controls { padding: 12px 14px 16px; background: var(--bg-primary); border-top: 1px solid var(--bg-tertiary); display: flex; flex-direction: column; gap: 10px; }
.ctl-row { display: flex; gap: 8px; }
.ctl {
  flex: 1; min-height: 48px;
  display: flex; align-items: center; justify-content: center;
  background: var(--bg-secondary); color: var(--text-primary);
  border-radius: var(--radius-md); font-size: 15px; font-weight: 600;
}

/* ---------- Quiz ---------- */
.quiz-body { flex: 1; display: flex; flex-direction: column; justify-content: center; padding: 16px 18px; gap: 22px; }
.quiz-prompt { text-align: center; }
.quiz-ask { font-size: 15px; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 1px; }
.quiz-name { font-size: 38px; font-weight: 800; color: var(--accent); margin-top: 10px; }
.quiz-answer.hidden-answer { visibility: hidden; }
.quiz-hint { text-align: center; font-size: 14px; color: var(--text-muted); min-height: 18px; }
.quiz-controls { padding: 12px 16px 18px; background: var(--bg-primary); border-top: 1px solid var(--bg-tertiary); display: flex; gap: 10px; }