* {
  box-sizing: border-box;
}

body {
  padding: 0 25px;
}

#demo {
  /* Forms a stacking context */
  isolation: isolate;
  /* Flattened */
  transform-style: flat;
  /* Explicit background color to stop the capture being transparent */
  background-color: white;
}

#demo > h2 {
  margin-top: 0;
}

#demo > p {
  border: 1px solid #ccc;
  margin: 0;
  padding: 5px;
  height: 320px;
}