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

body {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

canvas {
  display: block;
  box-sizing: content-box;
  border: 1px solid red;
}

#tip {
  background-color: skyblue;
  position: absolute;
  left: 0;
  top: 0;
  margin: 20px;
  padding: 10px 20px;
}
#tip p {
  margin: 2px;
}

#d2 {
  position: absolute;
  z-index: 1;
  left: 0;
  top: 0;
}

.lil-gui {
  --font-size: 16px;
  --input-font-size: 16px ;
}