:root {
  --ink: #0F1B2D;
  --paper: #ECEFEF;
  --accent: #E2762F;
  --line: rgba(236, 239, 239, 0.5);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--ink);
  color: var(--paper);
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  overflow: hidden;
}

#canvasHost {
  position: fixed;
  inset: 0;
}
#canvasHost canvas {
  display: block;
  width: 100%;
  height: 100%;
}

#labelHost {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  overflow: hidden;
}

.room-label {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--paper);
  background: rgba(15, 27, 45, 0.55);
  border-bottom: 2px solid var(--accent);
  padding: 0.35rem 0.7rem;
  white-space: nowrap;
  backdrop-filter: blur(4px);
  transform: translate(-50%, -100%);
}

.ui {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 2;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  padding: 1.25rem 1.5rem;
  pointer-events: none;
}

.ui__mark {
  font-family: 'IBM Plex Mono', monospace;
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--accent);
}

.ui__nav {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  pointer-events: auto;
}

.ui__btn {
  font-family: 'IBM Plex Sans', system-ui, sans-serif;
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.55rem 1rem;
  border-radius: 3px;
  border: 1px solid var(--line);
  background: rgba(15, 27, 45, 0.55);
  color: var(--paper);
  backdrop-filter: blur(6px);
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.ui__btn:hover { border-color: var(--accent); }
.ui__btn.is-active {
  background: var(--accent);
  color: #1A1006;
  border-color: var(--accent);
}