/* ── Reset & variables ─────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #141420;
  --bg2:       #1c1c2e;
  --bg3:       #24243a;
  --bg4:       #2e2e48;
  --accent:    #7b6cf6;
  --accent2:   #9f8fff;
  --green:     #4ade80;
  --red:       #f87171;
  --text:      #e2e2f0;
  --text-dim:  #7070a0;
  --border:    #303050;
  --radius:    6px;
  --toolbar-h: 50px;
  --footer-h:  28px;
  --nav-w:     220px;
  --ch-w:      84px;
}

html, body { height: 100%; font-family: 'Segoe UI', system-ui, sans-serif; font-size: 13px; background: var(--bg); color: var(--text); overflow: hidden; }

button { cursor: pointer; border: 1px solid var(--border); background: var(--bg3); color: var(--text); border-radius: var(--radius); padding: 5px 14px; font-size: 12px; transition: background .15s; }
button:hover { background: var(--bg4); }
button:disabled { opacity: .4; cursor: default; }
button.active { background: var(--accent); border-color: var(--accent); color: #fff; }

input[type=number], select { background: var(--bg3); color: var(--text); border: 1px solid var(--border); border-radius: var(--radius); padding: 3px 6px; font-size: 12px; }
input[type=number] { width: 56px; }
select { width: auto; }

input[type=range] { accent-color: var(--accent); width: 80px; vertical-align: middle; }

.dim { color: var(--text-dim); }
.hidden { display: none !important; }
.empty-msg { color: var(--text-dim); padding: 24px 16px; text-align: center; }

/* ── Toolbar ───────────────────────────────────────────── */
#toolbar {
  height: var(--toolbar-h);
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 0 16px;
  flex-shrink: 0;
}

#brand { display: flex; align-items: center; gap: 8px; font-weight: 600; color: var(--accent2); white-space: nowrap; }
#brand svg { color: var(--accent); }

#file-controls { display: flex; align-items: center; gap: 10px; flex: 1; }
#style-name { font-weight: 600; }

#style-meta { display: flex; align-items: center; gap: 12px; white-space: nowrap; }
#style-meta label { display: flex; align-items: center; gap: 6px; }

/* ── Main layout ───────────────────────────────────────── */
#main-layout {
  display: flex;
  height: calc(100vh - var(--toolbar-h) - var(--footer-h));
  overflow: hidden;
}

/* ── Section navigator ────────────────────────────────── */
#section-nav {
  width: var(--nav-w);
  min-width: var(--nav-w);
  background: var(--bg2);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#nav-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 12px;
  font-weight: 600;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--text-dim);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

#section-tree {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 6px 0;
}

/* tree groups */
.tree-group { margin-bottom: 2px; }

.tree-group-header {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--text-dim);
  cursor: pointer;
  user-select: none;
}
.tree-group-header:hover { color: var(--text); }
.tree-group-header .arrow { transition: transform .15s; display: inline-block; }
.tree-group-header.collapsed .arrow { transform: rotate(-90deg); }

.tree-group-items { padding: 0 0 4px 0; }

.tree-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px 6px 22px;
  cursor: pointer;
  border-left: 3px solid transparent;
  transition: background .1s;
  white-space: nowrap;
  overflow: hidden;
}
.tree-item:hover { background: var(--bg3); }
.tree-item.active { background: rgba(123,108,246,.15); border-left-color: var(--accent); color: var(--accent2); }
.tree-item.empty { color: var(--text-dim); font-style: italic; }

.tree-item .item-name { flex: 1; font-size: 12px; overflow: hidden; text-overflow: ellipsis; }
.tree-item .item-badge {
  font-size: 9px;
  padding: 1px 5px;
  border-radius: 3px;
  background: var(--bg4);
  color: var(--text-dim);
}
.tree-item.active .item-badge { background: rgba(123,108,246,.3); color: var(--accent2); }

/* ── Editor area ───────────────────────────────────────── */
#editor-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--bg);
}

#section-title-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  height: 44px;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

#section-label { font-weight: 700; font-size: 14px; }

#editor-tabs { display: flex; gap: 4px; }
.tab { padding: 4px 14px; }

.tab-content { flex: 1; display: flex; flex-direction: column; overflow: hidden; }

/* ── Channel mixer ─────────────────────────────────────── */
#channel-mixer-wrap { flex: 1; display: flex; flex-direction: column; overflow: hidden; }

#channel-mixer {
  display: flex;
  flex-direction: row;
  gap: 2px;
  padding: 16px;
  overflow-x: auto;
  overflow-y: auto;
  flex: 1;
  background: var(--bg);
}

.ch-strip {
  width: var(--ch-w);
  min-width: var(--ch-w);
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 10px 8px 14px;
  gap: 10px;
}

.ch-strip.drums { border-color: #60a5fa44; }
.ch-strip.muted { opacity: .5; }

.ch-label {
  font-size: 10px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .05em;
  color: var(--text-dim);
  width: 100%;
  text-align: center;
}

.ch-num {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}
.ch-strip.drums .ch-num { color: #60a5fa; }

/* program selector */
.ch-prog {
  width: 100%;
  font-size: 10px;
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 4px;
  padding: 2px 4px;
  text-align: center;
  cursor: pointer;
}
.ch-prog:focus { outline: 1px solid var(--accent); }

/* fader */
.fader-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  width: 100%;
}
.fader-label { font-size: 9px; color: var(--text-dim); text-transform: uppercase; letter-spacing: .05em; }

.fader-v {
  writing-mode: vertical-lr;
  direction: rtl;
  -webkit-appearance: slider-vertical;
  appearance: slider-vertical;
  width: 24px;
  height: 90px;
  accent-color: var(--green);
  cursor: pointer;
}

.fader-val { font-size: 10px; color: var(--text-dim); font-variant-numeric: tabular-nums; }

/* knob row */
.knob-row { display: flex; gap: 6px; align-items: flex-end; }

.knob-wrap { display: flex; flex-direction: column; align-items: center; gap: 3px; }
.knob-label { font-size: 9px; color: var(--text-dim); text-transform: uppercase; }

.knob {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: conic-gradient(var(--accent) 0deg, var(--bg4) 0deg);
  border: 2px solid var(--bg4);
  cursor: ew-resize;
  position: relative;
  user-select: none;
}
.knob::after {
  content: '';
  position: absolute;
  top: 3px;
  left: 50%;
  transform: translateX(-50%);
  width: 3px;
  height: 8px;
  background: var(--text);
  border-radius: 2px;
}
.knob-val { font-size: 9px; color: var(--text-dim); font-variant-numeric: tabular-nums; }

/* Mute button */
.ch-mute { font-size: 10px; padding: 2px 8px; border-radius: 3px; }
.ch-mute.muted { background: var(--red); border-color: var(--red); color: #fff; }

/* ── Piano Roll ────────────────────────────────────────── */
#piano-roll-toolbar {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 6px 12px;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  font-size: 11px;
  flex-wrap: wrap;
}
#piano-roll-toolbar label { display: flex; align-items: center; gap: 5px; color: var(--text-dim); }

.toolbar-sep { width: 1px; height: 22px; background: var(--border); flex-shrink: 0; }

/* Tool buttons */
#pr-tools { display: flex; gap: 2px; }
.tool-btn { padding: 4px 10px; font-size: 14px; line-height: 1; }
.tool-btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }

/* Undo/redo */
#btn-undo, #btn-redo { font-size: 16px; padding: 3px 10px; }

/* Velocity display */
#vel-val { font-variant-numeric: tabular-nums; min-width: 24px; }

#piano-roll-outer {
  display: flex;
  flex: 1;
  overflow: hidden;
  background: var(--bg);
}

#canvas-keys {
  flex-shrink: 0;
  background: var(--bg2);
  border-right: 1px solid var(--border);
}

#piano-roll-scroll {
  flex: 1;
  overflow: auto;
  position: relative;
}

#canvas-roll {
  display: block;
  cursor: crosshair;
}

/* Dirty indicator */
#dirty-badge { color: var(--accent2); font-size: 18px; line-height: 1; }

/* ── Footer ────────────────────────────────────────────── */
#statusbar {
  height: var(--footer-h);
  background: var(--bg2);
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  font-size: 11px;
  color: var(--text-dim);
  flex-shrink: 0;
}

/* ── Scrollbar styling ─────────────────────────────────── */
::-webkit-scrollbar { width: 7px; height: 7px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--bg4); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--border); }

/* ── Channel colors for piano roll ─────────────────────── */
:root {
  --ch0:  #7b6cf6;
  --ch1:  #22d3ee;
  --ch2:  #4ade80;
  --ch3:  #facc15;
  --ch4:  #fb923c;
  --ch5:  #f472b6;
  --ch6:  #a78bfa;
  --ch7:  #34d399;
  --ch8:  #f87171;
  --ch9:  #94a3b8;
  --ch10: #e879f9;
  --ch11: #38bdf8;
}