:root {
  --bg: #12101c;
  --panel: #1c1830;
  --panel2: #221d3a;
  --border: #322c50;
  --text: #ece8fb;
  --sub: #9b93bf;
  --accent: #61f0d6;
  --accent-dim: #2f6a5f;
  --bass: #f0669a;
  --bass-dim: #6e2c46;
  --drum: #f0c661;
  --drum-dim: #6e5a25;
  --danger: #ff6b6b;
  --radius: 12px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Hiragino Kaku Gothic ProN", "Yu Gothic", "Segoe UI", sans-serif;
  -webkit-tap-highlight-color: transparent;
}

#app {
  max-width: 1000px;
  margin: 0 auto;
  padding: 16px 16px 60px;
}

/* ---------- header ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 16px;
}
.topbar h1 {
  font-size: 22px;
  margin: 0;
  letter-spacing: 0.5px;
}
.topbar h1 span {
  color: var(--accent);
}
.versionBadge {
  font-size: 11px;
  color: var(--sub);
  margin-left: 6px;
}

/* ---------- generic controls ---------- */
.ghostBtn, .primaryBtn, .playBtn {
  background: var(--panel2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 13px;
  cursor: pointer;
  white-space: nowrap;
}
.ghostBtn:hover, .primaryBtn:hover, .playBtn:hover { border-color: var(--accent); }
.primaryBtn {
  background: var(--accent);
  color: #0a1c18;
  font-weight: bold;
  border-color: var(--accent);
}
.dangerBtn:hover { border-color: var(--danger); color: var(--danger); }
.fileLabel { display: inline-flex; align-items: center; }

.ctrl {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--sub);
}
.checkCtrl { flex-direction: row-reverse; }
select, input[type="number"] {
  background: var(--panel2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 6px;
  padding: 5px 6px;
  font-size: 13px;
}
input[type="range"] { accent-color: var(--accent); }

/* ---------- transport ---------- */
.transportBar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 16px;
  margin-bottom: 16px;
}
.playBtn {
  font-size: 15px;
  padding: 10px 18px;
  min-width: 100px;
}
.playBtn.playing { background: var(--accent); color: #0a1c18; border-color: var(--accent); }
.bpmInput { width: 56px; }
.bpmRange { width: 100px; }
.bpmDisplay { min-width: 30px; color: var(--text); font-weight: bold; }
.masterVolRange { width: 100px; }

/* ---------- chord helper ---------- */
.chordHelper {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin-bottom: 16px;
}
.chordHelper h2 { margin: 0 0 10px; font-size: 15px; }
.keyRow { display: flex; gap: 16px; margin-bottom: 12px; flex-wrap: wrap; }
.diatonicChords {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 14px;
}
.chordChip {
  display: flex;
  flex-direction: column;
  align-items: center;
  background: var(--panel2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 4px 10px;
  min-width: 44px;
}
.chordRoman { font-size: 10px; color: var(--sub); }
.chordSym { font-size: 14px; font-weight: bold; }
.progressionList {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 10px;
}
.progBtn {
  background: var(--panel2);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 20px;
  padding: 6px 14px;
  font-size: 12px;
  cursor: pointer;
}
.progBtn.active { border-color: var(--accent); color: var(--accent); background: rgba(97,240,214,0.1); }
.progPreviewRow {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}
.progressionPreview {
  font-size: 15px;
  font-weight: bold;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
}
.chordArrow { color: var(--sub); font-weight: normal; }
.applyRow {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

/* ---------- tracks ---------- */
.tracksSection { margin-bottom: 16px; }
.tracksHead {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 10px;
}
.tracksHead h2 { margin: 0; font-size: 15px; }
.addTrackBtns { display: flex; gap: 6px; flex-wrap: wrap; }

.tracksContainer { display: flex; flex-direction: column; gap: 14px; }

.trackPanel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.trackHeader {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  padding: 8px 10px;
  background: var(--panel2);
  border-bottom: 1px solid var(--border);
}
.trackIcon { font-size: 16px; }
.trackName {
  width: 90px;
  background: transparent;
  border: 1px solid transparent;
  color: var(--text);
  font-size: 13px;
  font-weight: bold;
  border-radius: 6px;
  padding: 4px 6px;
}
.trackName:hover, .trackName:focus { border-color: var(--border); background: var(--panel); }
.drumTag { font-size: 11px; color: var(--sub); }
.volLabel { display: flex; align-items: center; gap: 4px; font-size: 11px; color: var(--sub); }
.trackVol { width: 70px; }
.muteBtn, .soloBtn, .clearTrackBtn, .removeTrackBtn {
  background: var(--panel);
  border: 1px solid var(--border);
  color: var(--sub);
  border-radius: 6px;
  width: 26px;
  height: 26px;
  cursor: pointer;
  font-size: 12px;
  line-height: 1;
}
.muteBtn.active { background: var(--danger); color: #2a0a0a; border-color: var(--danger); }
.soloBtn.active { background: var(--drum); color: #2a1c00; border-color: var(--drum); }
.removeTrackBtn:hover { border-color: var(--danger); color: var(--danger); }
.trackHeader > * { margin-left: 0; }
.trackHeader > .muteBtn { margin-left: auto; }

.gridWrap { overflow-x: auto; }
.pianoGrid { display: flex; flex-direction: column; min-width: max-content; }
.gridRow { display: flex; align-items: stretch; }
.gridRow.blackRow { background: rgba(0,0,0,0.18); }
.rowLabel {
  width: 52px;
  flex: 0 0 52px;
  font-size: 10px;
  color: var(--sub);
  display: flex;
  align-items: center;
  justify-content: flex-end;
  padding-right: 6px;
  position: sticky;
  left: 0;
  background: var(--panel);
  z-index: 2;
}
.gridRow.blackRow .rowLabel { background: #17132a; }
.stepsRow { display: flex; }
.stepCol {
  width: 22px;
  height: 20px;
  flex: 0 0 22px;
  border-right: 1px solid rgba(255,255,255,0.04);
  border-bottom: 1px solid rgba(255,255,255,0.04);
  cursor: pointer;
}
.stepCol.altBeat { background: rgba(255,255,255,0.02); }
.stepCol.barStart { border-left: 2px solid var(--border); }
.stepCol:hover { background: rgba(255,255,255,0.08); }
.stepCol.playhead { background: rgba(255,255,255,0.14); }

.track-melody .stepCol.active { background: var(--accent); }
.track-bass .stepCol.active { background: var(--bass); }
.track-drum .stepCol.active { background: var(--drum); }
.track-melody .stepCol.active.playhead { background: #a2ffe9; }
.track-bass .stepCol.active.playhead { background: #ffb0cd; }
.track-drum .stepCol.active.playhead { background: #ffe29e; }

/* ---------- footer ---------- */
.footerBar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 20px;
}

/* ---------- changelog modal ---------- */
.modalOverlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  display: none;
  align-items: center;
  justify-content: center;
  padding: 20px;
  z-index: 50;
}
.modalOverlay.open { display: flex; }
.modalBox {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  max-width: 480px;
  width: 100%;
  max-height: 80vh;
  display: flex;
  flex-direction: column;
}
.modalHead {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
}
.modalHead h2 { margin: 0; font-size: 15px; }
.closeBtn {
  background: none;
  border: none;
  color: var(--sub);
  font-size: 16px;
  cursor: pointer;
}
.changelogList { overflow-y: auto; padding: 12px 16px; }
.changeEntry { margin-bottom: 14px; }
.changeHead { display: flex; gap: 8px; align-items: baseline; margin-bottom: 4px; }
.changeVer { color: var(--accent); font-weight: bold; font-size: 13px; }
.changeDate { color: var(--sub); font-size: 11px; }
.changeEntry ul { margin: 0; padding-left: 18px; font-size: 13px; color: var(--text); }
.changeEntry li { margin-bottom: 3px; }

/* ---------- responsive ---------- */
@media (max-width: 600px) {
  .topbar h1 { font-size: 18px; }
  .transportBar { gap: 10px; padding: 10px; }
  .bpmRange, .masterVolRange { width: 70px; }
  .rowLabel { width: 40px; flex-basis: 40px; font-size: 9px; }
  .stepCol { width: 18px; flex-basis: 18px; height: 18px; }
}