/* Lock /embed/proof to a 400px transparent frame. */
html,
body {
  box-sizing: border-box !important;
  width: 100% !important;
  height: 400px !important;
  min-height: 400px !important;
  max-height: 400px !important;
  margin: 0 !important;
  padding: 0 !important;
  overflow: hidden !important;
  overscroll-behavior: auto !important;
  background-color: transparent !important;
}

body {
  position: relative !important;
  touch-action: pan-y pinch-zoom !important;
  overscroll-behavior: auto !important;
}

body > div:first-of-type,
body > div:first-of-type > div,
body main {
  box-sizing: border-box !important;
  height: 400px !important;
  min-height: 400px !important;
  max-height: 400px !important;
  overflow: hidden !important;
}