.preview iframe {
  background-color: #181818;
  background-image:
    linear-gradient(45deg, #252525 25%, transparent 25%),
    linear-gradient(-45deg, #252525 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #252525 75%),
    linear-gradient(-45deg, transparent 75%, #252525 75%);
  background-position: 0 0, 0 16px, 16px -16px, -16px 0;
  background-size: 32px 32px;
}

html input[type="checkbox"] {
  position: relative;
  justify-self: end;
  width: 60px;
  height: 34px;
  margin: 0;
  padding: 0;
  border: 0;
  border-radius: 34px;
  outline: 0;
  appearance: none;
  -webkit-appearance: none;
  background-color: #ccc;
  cursor: pointer;
  transition: background-color 0.4s;
}

html input[type="checkbox"]::before {
  position: absolute;
  bottom: 4px;
  left: 4px;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background-color: #fff;
  content: "";
  transition: transform 0.4s;
}

html input[type="checkbox"]:checked {
  background-color: #2196f3;
}

html input[type="checkbox"]:checked::before {
  transform: translateX(26px);
}

html input[type="checkbox"]:focus-visible {
  box-shadow: 0 0 0 3px rgba(33, 150, 243, 0.35);
}