html,
body {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

iframe {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  height: 100%;
  max-width: 100%;
  max-height: 100%;
  border: 0;
  margin: 0;
  padding: 0;
  background: #fff;
  pointer-events: auto !important;
  /* allow one-finger scroll; block pinch-zoom */
  touch-action: pan-x pan-y;
  overflow: auto;
  -webkit-overflow-scrolling: touch;
}