<div></div>

div {
  width: 200px;
  height: 100px;
  position: relative;
  border-radius: 10px;
  background: linear-gradient(135deg, transparent 5%, red 5%);
}
div::before {
  content: '';
  position: absolute;
  left: 3px;
  right: 3px;
  top: 3px;
  bottom: 3px;
  border-radius: 7px;
  background: linear-gradient(135deg, transparent 4%, orange 5%);
}