html, body {
  width: 100%;
  height: 100%;
}

html {
  overscroll-behavior: none;
}

body {
  overflow: hidden;
  overscroll-behavior-y: contain;
  margin: 0;
  background-color: green;
}

canvas {
  display: block;  /* prevents scrollbar */
  width: 100vw;
  height: 100vh;
}