:root {
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", sans-serif;
  --bg: #000;
  --bg-gradient-top: #1c1c1e;
  --surface: rgba(28, 28, 30, 0.72);
  --surface-solid: #1c1c1e;
  --surface-hover: #2c2c2e;
  --text: #f5f5f7;
  --text-secondary: rgba(245, 245, 247, 0.6);
  --accent: #0a84ff;
  --accent-tint: rgba(10, 132, 255, 0.15);
  --accent-hover: #fa2d48;
  --divider: rgba(255, 255, 255, 0.08);
  --radius: 10px;
  --ease: 180ms cubic-bezier(0.25, 0.1, 0.25, 1);
  --blur: blur(20px) saturate(180%);
  --player-h: 88px;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f5f5f7;
    --bg-gradient-top: #fff;
    --surface: rgba(255, 255, 255, 0.78);
    --surface-solid: #fff;
    --surface-hover: #e8e8ed;
    --text: #1d1d1f;
    --text-secondary: rgba(29, 29, 31, 0.6);
    --accent-tint: rgba(10, 132, 255, 0.12);
    --divider: rgba(0, 0, 0, 0.08);
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

*, *::before, *::after { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  font-family: var(--font);
  background: linear-gradient(180deg, var(--bg-gradient-top) 0%, var(--bg) 40%);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

button, input { font: inherit; color: inherit; }

.app {
  display: flex;
  flex-direction: column;
  min-height: 100%;
  padding-bottom: var(--player-h);
}

.app.player-visible { padding-bottom: var(--player-h); }

.header {
  padding: 1.25rem 1.5rem 0.75rem;
}

.header-title {
  margin: 0;
  font-size: 1.75rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}

.mobile-nav {
  display: none;
  gap: 0.5rem;
  margin-top: 0.75rem;
  overflow-x: auto;
}

.mobile-nav button {
  flex-shrink: 0;
  padding: 0.4rem 0.9rem;
  border: none;
  border-radius: 999px;
  background: var(--surface-solid);
  color: var(--text-secondary);
  cursor: pointer;
  transition: background var(--ease), color var(--ease);
}

.mobile-nav button.active {
  background: var(--accent-tint);
  color: var(--accent);
}

.main {
  display: flex;
  flex: 1;
  min-height: 0;
}

.sidebar {
  width: 220px;
  flex-shrink: 0;
  padding: 0.75rem 0.75rem 1.5rem 1.5rem;
  background: var(--surface);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  border-right: 1px solid var(--divider);
}

.sidebar-label {
  margin: 0 0 0.5rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
}

.sidebar-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sidebar-item button {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  width: 100%;
  padding: 0.55rem 0.75rem;
  border: none;
  border-radius: var(--radius);
  background: transparent;
  color: var(--text);
  text-align: left;
  cursor: pointer;
  transition: background var(--ease);
  position: relative;
}

.sidebar-item button:hover { background: var(--surface-hover); }

.sidebar-item.active button {
  background: var(--accent-tint);
  color: var(--accent);
}

.sidebar-item.active button::before {
  content: "";
  position: absolute;
  left: 0;
  top: 20%;
  bottom: 20%;
  width: 3px;
  border-radius: 2px;
  background: var(--accent);
}

.sidebar-item svg {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  opacity: 0.7;
}

.library {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: 0.75rem 1.5rem 1.5rem;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.25rem;
  margin-bottom: 0.75rem;
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

.breadcrumb button {
  border: none;
  background: none;
  padding: 0.2rem 0.35rem;
  border-radius: 6px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: color var(--ease), background var(--ease);
}

.breadcrumb button:hover {
  color: var(--text);
  background: var(--surface-hover);
}

.breadcrumb button.current {
  color: var(--text);
  cursor: default;
}

.breadcrumb-sep { opacity: 0.4; user-select: none; }

.library-list {
  flex: 1;
  overflow-y: auto;
  border-radius: var(--radius);
}

.row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 0.85rem;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background var(--ease);
  outline: none;
}

.row:hover, .row:focus-visible { background: var(--surface-hover); }

.row.playing {
  background: var(--accent-tint);
  color: var(--accent);
}

.row-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  opacity: 0.55;
}

.row.playing .row-icon { opacity: 1; }

.row-name {
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: 0.9375rem;
}

.row-meta {
  font-size: 0.8125rem;
  font-variant-numeric: tabular-nums;
  color: var(--text-secondary);
}

.row.playing .row-meta { color: var(--accent); opacity: 0.8; }

.row-chevron {
  width: 14px;
  height: 14px;
  opacity: 0.35;
}

.equalizer {
  display: flex;
  align-items: flex-end;
  gap: 2px;
  width: 16px;
  height: 14px;
  flex-shrink: 0;
}

.equalizer span {
  display: block;
  width: 3px;
  background: var(--accent);
  border-radius: 1px;
  animation: eq 0.9s ease-in-out infinite;
}

.equalizer span:nth-child(1) { animation-delay: 0s; }
.equalizer span:nth-child(2) { animation-delay: 0.15s; }
.equalizer span:nth-child(3) { animation-delay: 0.3s; }

@keyframes eq {
  0%, 100% { height: 4px; }
  50% { height: 14px; }
}

.loading, .empty-state {
  margin: 2rem 0;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.9375rem;
}

.player {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  display: grid;
  grid-template-columns: 1fr auto;
  grid-template-rows: auto auto;
  gap: 0.35rem 1.5rem;
  padding: 0.75rem 1.5rem;
  background: var(--surface);
  backdrop-filter: var(--blur);
  -webkit-backdrop-filter: var(--blur);
  border-top: 1px solid var(--divider);
  box-shadow: 0 -4px 24px rgba(0, 0, 0, 0.18);
  transform: translateY(100%);
  transition: transform var(--ease);
}

.player.visible {
  transform: translateY(0);
}

.player-track {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  min-width: 0;
  grid-column: 1;
  grid-row: 1;
}

.player-title {
  margin: 0;
  font-size: 0.9375rem;
  font-weight: 500;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.player-controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  grid-column: 1 / -1;
  grid-row: 2;
}

.time {
  font-size: 0.75rem;
  font-variant-numeric: tabular-nums;
  color: var(--text-secondary);
  min-width: 2.5rem;
}

.time:last-of-type { text-align: right; }

.scrubber {
  flex: 1;
  height: 20px;
  display: flex;
  align-items: center;
  cursor: pointer;
}

.scrubber-track {
  position: relative;
  width: 100%;
  height: 4px;
  background: var(--divider);
  border-radius: 2px;
}

.scrubber-fill {
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: 0%;
  background: var(--accent);
  border-radius: 2px;
  transition: width 80ms linear;
}

.scrubber-thumb {
  position: absolute;
  top: 50%;
  left: 0%;
  width: 12px;
  height: 12px;
  margin: -6px 0 0 -6px;
  background: var(--text);
  border-radius: 50%;
  opacity: 0;
  transition: opacity var(--ease);
}

.scrubber:hover .scrubber-thumb,
.scrubber:focus-visible .scrubber-thumb { opacity: 1; }

.player-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
  grid-column: 2;
  grid-row: 1;
}

.btn-play {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: none;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  transition: transform var(--ease), background var(--ease);
}

.btn-play:hover { background: var(--accent-hover); }
.btn-play:active { transform: scale(0.96); }

.btn-play svg { width: 20px; height: 20px; }

.volume {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.icon-volume {
  width: 18px;
  height: 18px;
  opacity: 0.6;
}

.volume-slider {
  width: 80px;
  accent-color: var(--accent);
}

@media (max-width: 768px) {
  .sidebar { display: none; }
  .mobile-nav { display: flex; }
  .library { padding: 0.5rem 1rem 1rem; }
  .player {
    grid-template-columns: 1fr;
    padding: 0.65rem 1rem;
  }
  .player-actions {
    grid-column: 1;
    grid-row: 3;
    justify-content: center;
  }
  .volume-slider { width: 120px; }
}