pointer

<input id="test" type="checkbox" /> <label for="test">これを見て！</label>

input[type="checkbox"] {
  appearance: none;
  border: solid;
  margin: 0;
}
input[type="checkbox"]:checked {
  background: gray;
}
@media (pointer: fine) {
  input[type="checkbox"] {
    width: 15px;
    height: 15px;
    border-width: 1px;
    border-color: blue;
  }
}
@media (pointer: coarse) {
  input[type="checkbox"] {
    width: 30px;
    height: 30px;
    border-width: 2px;
    border-color: red;
  }
}