:root {
  --bg: #0f1220;
  --card: #1a1e33;
  --card-2: #232842;
  --text: #e8eaf6;
  --muted: #9aa0c3;
  --accent: #6c7bff;
  --accent-2: #4b58d6;
  --good: #3ddc84;
  --bad: #ff6b6b;
  --line: #cdd2f0;
  --staff-bg: #fbfbff;
  --staff-ink: #14161f;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family:
    system-ui,
    -apple-system,
    "Segoe UI",
    Roboto,
    sans-serif;
  background: radial-gradient(1200px 600px at 50% -10%, #202545, var(--bg));
  color: var(--text);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 24px 16px 48px;
}

.app {
  width: 100%;
  max-width: 560px;
}

header {
  text-align: center;
  margin-bottom: 18px;
}
h1 {
  margin: 0;
  font-size: 1.9rem;
  letter-spacing: 0.5px;
}
.subtitle {
  margin: 4px 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.mode-picker {
  display: flex;
  gap: 12px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}
.seg-group {
  flex: 1;
  min-width: 220px;
  background: var(--card);
  border-radius: 14px;
  padding: 8px 10px 10px;
}
.seg-label {
  display: block;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--muted);
  margin: 2px 0 6px 2px;
}
.seg {
  display: flex;
  gap: 6px;
}
.seg-btn {
  flex: 1;
  border: 0;
  padding: 9px 6px;
  border-radius: 9px;
  background: transparent;
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: 0.15s;
}
.seg-btn:hover:not(:disabled) {
  background: var(--card-2);
}
.seg-btn.active {
  background: var(--accent);
  color: #fff;
  box-shadow: 0 6px 18px -8px var(--accent);
}
.seg-btn:disabled {
  opacity: 0.28;
  cursor: not-allowed;
}

.card {
  background: var(--card);
  border-radius: 18px;
  padding: 20px;
  box-shadow: 0 20px 50px -30px #000;
}

.prompt {
  font-size: 1.15rem;
  text-align: center;
  min-height: 3.2em;
  line-height: 1.5;
}
.prompt strong {
  color: var(--accent);
  font-size: 1.35em;
}
.hint {
  display: inline-block;
  color: var(--muted);
  font-size: 0.82rem;
  margin-top: 4px;
}

.staff {
  width: 100%;
  height: auto;
  background: var(--staff-bg);
  border-radius: 12px;
  margin: 6px 0;
  display: block;
  user-select: none;
}
.staff.interactive {
  cursor: crosshair;
}
.staff.hidden {
  display: none;
}

.keyboard {
  width: 100%;
  height: auto;
  background: var(--staff-bg);
  border-radius: 12px;
  margin: 6px 0;
  display: block;
  user-select: none;
}
.keyboard.hidden {
  display: none;
}
.keyboard.interactive .key {
  cursor: pointer;
}
.key.white {
  fill: #f7f8ff;
  stroke: #3a3f5a;
  stroke-width: 1;
}
.key.black {
  fill: #1c2033;
  stroke: #05060c;
  stroke-width: 1;
}
.key.selected {
  fill: var(--accent);
}
.key.highlight {
  fill: var(--accent);
}
.key.correct {
  fill: var(--good);
}
.key-label {
  font-size: 9px;
  fill: #9aa0c3;
  text-anchor: middle;
  pointer-events: none;
}

.staff-line {
  stroke: #444a63;
  stroke-width: 1.4;
}
.ledger {
  stroke: var(--staff-ink);
  stroke-width: 1.6;
}
.clef {
  font-size: 84px;
  fill: var(--staff-ink);
}
.notehead {
  fill: var(--staff-ink);
}
.notehead.placed {
  fill: var(--accent-2);
}
.accidental {
  font-size: 26px;
  fill: var(--staff-ink);
  text-anchor: middle;
}

.readout {
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
  min-height: 1.3em;
  font-variant-numeric: tabular-nums;
}

.controls {
  display: flex;
  align-items: center;
  gap: 10px;
  justify-content: center;
  margin: 12px 0 4px;
  flex-wrap: wrap;
}
.controls.hidden {
  display: none;
}
.select.hidden {
  display: none;
}

.acc-group {
  display: flex;
  align-items: center;
  gap: 6px;
}
.acc-label {
  color: var(--muted);
  font-size: 0.9rem;
}
.midi-status {
  font-size: 0.82rem;
  color: var(--muted);
}
.midi-status.on {
  color: var(--good);
}
.midi-status.err {
  color: var(--bad);
}
.acc-btn {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  border: 1px solid var(--card-2);
  background: var(--card-2);
  color: var(--text);
  font-size: 1.3rem;
  cursor: pointer;
}
.acc-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.text-input,
.select {
  padding: 12px 14px;
  border-radius: 10px;
  border: 1px solid var(--card-2);
  background: var(--card-2);
  color: var(--text);
  font-size: 1rem;
}
.text-input {
  flex: 1;
  min-width: 180px;
}
.text-input:focus,
.select:focus {
  outline: 2px solid var(--accent);
}

.actions {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin-top: 14px;
}
.btn {
  border: 0;
  padding: 12px 18px;
  border-radius: 10px;
  background: var(--card-2);
  color: var(--text);
  font-size: 0.98rem;
  font-weight: 600;
  cursor: pointer;
  transition: 0.15s;
}
.btn:hover {
  filter: brightness(1.12);
}
.btn.primary {
  background: var(--accent);
  color: #fff;
}
.btn.primary:disabled {
  opacity: 0.5;
  cursor: default;
}
.btn.ghost {
  background: transparent;
  border: 1px solid var(--card-2);
}

.feedback {
  min-height: 1.5em;
  text-align: center;
  margin-top: 14px;
  font-size: 1rem;
}
.feedback.good {
  color: var(--good);
  font-weight: 600;
}
.feedback.bad {
  color: var(--bad);
  font-weight: 600;
}

.stats {
  display: flex;
  gap: 10px;
  margin-top: 16px;
}
.stats > div {
  flex: 1;
  background: var(--card);
  border-radius: 12px;
  padding: 12px;
  text-align: center;
}
.stats span {
  font-size: 1.5rem;
  font-weight: 700;
  display: block;
}
.stats small {
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 1px;
  font-size: 0.7rem;
}

.settings {
  margin-top: 16px;
  background: var(--card);
  border-radius: 12px;
  padding: 6px 16px;
}
.settings summary {
  cursor: pointer;
  padding: 10px 0;
  font-weight: 600;
}
.settings-group {
  margin: 8px 0 14px;
}
.settings-group h3 {
  margin: 6px 0 8px;
  font-size: 0.85rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}
.chip-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--card-2);
  padding: 7px 11px;
  border-radius: 20px;
  font-size: 0.88rem;
  cursor: pointer;
  user-select: none;
}
.chip input {
  accent-color: var(--accent);
}