html,
body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
}

body {
  font-family: "Trebuchet MS", "Segoe UI", sans-serif;
  background: #000;
}

.scene {
  position: relative;
  width: 100%;
  height: 100%;
  background: #000;
  touch-action: none;
}

#stage {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  cursor: crosshair;
  touch-action: none;
}

.shape-controls {
  position: absolute;
  top: 1rem;
  right: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  z-index: 5;
}

.shape-btn {
  width: 2.2rem;
  height: 2.2rem;
  border-radius: 0.55rem;
  border: 1px solid rgba(255, 255, 255, 0.22);
  background: rgba(18, 18, 18, 0.84);
  color: #f5f5f5;
  font-size: 1.05rem;
  line-height: 1;
  cursor: pointer;
  transition: transform 140ms ease, border-color 140ms ease;
  touch-action: manipulation;
}

.shape-btn:hover {
  transform: translateY(-1px);
  border-color: rgba(255, 255, 255, 0.5);
}

.shape-btn.is-active {
  border-color: rgba(255, 255, 255, 0.92);
}