.bg-canvas {
  position: fixed;
  top: 0; left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 1;          
  will-change: contents;
  transform: translateZ(0);   
}

.theme-picker {
  position: fixed;
  right: 16px;
  bottom: 16px;
  display: flex;
  gap: 2px;
  z-index: 60;
  background: rgba(14, 14, 16, 0.78);
  border: 1px solid var(--line);
  backdrop-filter: blur(10px) saturate(140%);
  -webkit-backdrop-filter: blur(10px) saturate(140%);
  padding: 4px;
}
.theme-picker::before {
  content: "BG //";
  font-family: var(--f-mono);
  font-size: 0.66rem;
  letter-spacing: .16em;
  color: var(--text-faint);
  align-self: center;
  padding: 0 8px 0 4px;
  text-transform: uppercase;
}
.theme-picker button {
  font-family: var(--f-mono);
  font-size: 0.66rem;
  letter-spacing: .14em;
  color: var(--text-dim);
  text-transform: uppercase;
  padding: 6px 10px;
  border: 1px solid transparent;
  background: transparent;
  cursor: pointer;
  transition: color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}
.theme-picker button:hover { color: var(--orange); }
.theme-picker button.active {
  color: var(--orange);
  border-color: var(--orange);
}

@media (max-width: 640px) {
  .theme-picker { right: 8px; bottom: 8px; }
  .theme-picker::before { padding: 0 4px 0 2px; }
  .theme-picker button { padding: 5px 8px; font-size: 0.62rem; }
}

@media (prefers-reduced-motion: reduce) {
  .bg-canvas { display: none; }
}