body {
  background: #1e1e1e;
  color: #f0f0f0;
  font-family: 'Segoe UI', sans-serif;
  text-align: center;
  padding: 20px;
}

canvas {
  border: 2px solid #f0f0f0;
  background: #000;
  cursor: crosshair;
}

.controls {
  margin-top: 15px;
}

button,
input[type="color"],
input[type="range"],
select,
input[type="checkbox"] {
  padding: 10px 20px;
  margin: 5px;
  background: #444;
  color: #fff;
  border: none;
  border-radius: 5px;
  font-weight: bold;
  cursor: pointer;
}

button:hover,
select:hover {
  background: #666;
}

label {
  margin-right: 10px;
  font-weight: bold;
}

.rainbow-on {
  background: linear-gradient(to right, red, orange, yellow, green, blue, indigo, violet);
  color: #fff;
  border: 2px solid #fff;
}