html, body {
  height: 100%;
  
  background: rgb(0, 0, 0);
}

body {
  margin: 0;
  display: flex;

  /* This centers our sketch horizontally. */
  justify-content: center;

  /* This centers our sketch vertically. */
  align-items: center;
}

main canvas { 
  
  max-width: 100%;
  max-height: 100%;
  display: block; /* Instead of display: block; */
  margin: 0 auto;
  vertical-align: middle;
  touch-action: none;
}
  
  
/* style.css */