html, body {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  margin: 0; padding: 0;
  overflow-x: hidden;               /* no scrollbars */
  overscroll-behavior: none;      /* kill bounce on supporting browsers */
  -webkit-overflow-scrolling: auto; /* disable momentum scrolling */
}