:root {
  --bg: #0f1115;
  --panel: #181b22;
  --panel-2: #20242d;
  --fg: #e6e8ee;
  --muted: #8a93a4;
  --accent: #6ea8ff;
  --accent-2: #4cd1a7;
  --warn: #ffb35c;
  --danger: #ff6b6b;
  --border: #2a2f3a;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.4;
}

header {
  text-align: center;
  padding: 2rem 1rem 1rem;
}
header h1 {
  margin: 0;
  font-size: 2.5rem;
  letter-spacing: -0.02em;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.tagline {
  margin: 0.25rem 0 0;
  color: var(--muted);
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

section {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

button {
  font: inherit;
  background: var(--panel-2);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 1rem;
  cursor: pointer;
  transition: background 0.15s, transform 0.05s;
}
button:hover:not(:disabled) { background: #2a2f3a; }
button:active:not(:disabled) { transform: translateY(1px); }
button:disabled { opacity: 0.45; cursor: not-allowed; }
button.primary { background: var(--accent); color: #0a1020; border-color: transparent; font-weight: 600; }
button.primary:hover:not(:disabled) { background: #8cbcff; }
button.ghost { background: transparent; }

.auto-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
  align-items: center;
  color: var(--muted);
}
.auto-controls label {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}
.auto-controls input[type="number"] {
  width: 4rem;
  background: var(--panel-2);
  color: var(--fg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.25rem 0.4rem;
  font: inherit;
}
.auto-controls input[type="range"] { width: 9rem; }
#thresholdLabel {
  font-variant-numeric: tabular-nums;
  color: var(--fg);
  min-width: 3.5ch;
  display: inline-block;
}

.meter {
  position: relative;
  height: 14px;
  background: var(--panel-2);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 0.5rem;
}
.meter-bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent-2), var(--accent), var(--warn));
  transition: width 0.05s linear;
}
.meter-threshold {
  position: absolute;
  top: -2px;
  bottom: -2px;
  width: 2px;
  background: var(--danger);
  left: 0%;
  pointer-events: none;
}
.status-text {
  color: var(--muted);
  font-size: 0.92rem;
  font-variant-numeric: tabular-nums;
  min-height: 1.3em;
}

.songs-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}
.songs-header h2 { margin: 0; font-size: 1.1rem; font-weight: 600; }

.song-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.song-list li {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  animation: fadeIn 0.3s ease-out;
}
.song-list .title { font-weight: 600; }
.song-list .artist { color: var(--muted); font-size: 0.92rem; }
.song-list .meta {
  color: var(--muted);
  font-size: 0.8rem;
  font-variant-numeric: tabular-nums;
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to   { opacity: 1; transform: translateY(0); }
}

.empty-hint {
  color: var(--muted);
  font-style: italic;
  margin: 0.5rem 0 0;
}
.empty-hint.hidden { display: none; }