:root {
  --bg: #12141a;
  --panel-bg: #1b1e27;
  --text: #e7e9ee;
  --text-dim: #9099ab;
  --border: #2a2e3a;
  --accent: #4fd1c5;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

.rnbo-header {
  padding: 2rem 1.5rem 1rem;
  text-align: center;
}
.rnbo-header h1 {
  margin: 0;
  font-size: 1.8rem;
  letter-spacing: 0.02em;
}
.rnbo-subtitle {
  margin: 0.25rem 0 0;
  color: var(--text-dim);
  font-size: 0.9rem;
}

main {
  max-width: 900px;
  margin: 0 auto;
  padding: 1rem 1.5rem 3rem;
}

.rnbo-sections {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.rnbo-panel {
  background: var(--panel-bg);
  border: 1px solid var(--border);
  border-top: 3px solid var(--accent);
  border-radius: 12px;
  padding: 1.25rem 1.5rem 1.5rem;
}
.rnbo-panel h2 {
  margin: 0 0 1rem;
  font-size: 1.05rem;
  color: var(--accent);
}

.rnbo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 1rem 1.5rem;
}

.rnbo-control label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-dim);
  margin-bottom: 0.35rem;
}

.rnbo-slider-row {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}
.rnbo-slider-row input[type="range"] {
  flex: 1;
  accent-color: var(--accent);
}
.rnbo-readout {
  font-variant-numeric: tabular-nums;
  font-size: 0.8rem;
  color: var(--text-dim);
  min-width: 3.5em;
  text-align: right;
}

.rnbo-control select {
  width: 100%;
  padding: 0.4rem 0.5rem;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
}

.rnbo-midi-select {
  margin-top: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  font-size: 0.85rem;
  color: var(--text-dim);
}
.rnbo-midi-select select {
  background: var(--panel-bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.35rem 0.5rem;
}
.rnbo-midi-unsupported {
  color: var(--text-dim);
  font-size: 0.8rem;
  text-align: center;
}
.rnbo-midi-refresh {
  background: var(--panel-bg);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 6px;
  padding: 0.3rem 0.6rem;
  cursor: pointer;
  font-size: 0.9rem;
  line-height: 1;
}
.rnbo-midi-refresh:hover { border-color: var(--accent); }

.rnbo-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0 0.25rem 1rem;
}
.rnbo-status {
  margin: 0;
  color: var(--text-dim);
  font-size: 0.8rem;
}
.rnbo-status-error { color: #f87171; }
.rnbo-power-btn {
  background: var(--panel-bg);
  border: 1px solid var(--border);
  color: var(--text-dim);
  border-radius: 999px;
  padding: 0.4rem 1rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
}
.rnbo-power-btn.is-on {
  background: var(--accent);
  color: #0b0c0f;
  border-color: var(--accent);
}

.rnbo-keyboard {
  margin-top: 2rem;
  text-align: center;
}
.rnbo-keyboard h2 {
  font-size: 1rem;
  color: var(--text-dim);
  font-weight: 500;
}
.rnbo-piano-wrap {
  display: flex;
  justify-content: center;
  overflow-x: auto;
  padding: 0.5rem;
}
.rnbo-piano { user-select: none; }
.rnbo-key-white {
  fill: #f4f4f4;
  stroke: #0b0c0f;
  stroke-width: 1;
  cursor: pointer;
}
.rnbo-key-white.is-active {
  fill: var(--accent);
}
.rnbo-key-black {
  fill: #16181f;
  stroke: #0b0c0f;
  stroke-width: 1;
  cursor: pointer;
}
.rnbo-key-black.is-active {
  fill: var(--accent);
}

.rnbo-footer {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.75rem;
  padding: 1.5rem;
}