html,
body {
  margin: 0;
  padding: 0;
  background: #0f0f0f;
}

canvas {
  display: block;
    background-image:
    repeating-linear-gradient(
      0deg,
      rgba(255,255,255,0.05) 0,
      rgba(255,255,255,0.05) 1px,
      transparent 1px,
      transparent 20px
    ),
    repeating-linear-gradient(
      90deg,
      rgba(255,255,255,0.05) 0,
      rgba(255,255,255,0.05) 1px,
      transparent 1px,
      transparent 20px
    );
  background-size: cover;
}

#ui {
  position: fixed;
  top: 10px;
  left: 10px;
  background: #111;
  color: #fff;
  font: 12px sans-serif;
  padding: 8px;
  border-radius: 6px;
  border: 1px solid #5e5e5e;
}

#ui label {
  display: flex;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 6px;
}

input {
  width: 120px;
}

button {
  margin-top: 6px;
  width: 100%;
}