将CSS添加到HTML复选框

<label class="custom-checkbox">
  <input type="checkbox" name="example" value="1">
  <span class="checkmark"></span>
  Option 1
</label>

/* Hide the default checkbox */
.custom-checkbox input[type="checkbox"] {
  display: none;
}

/* Create a custom checkbox */
.custom-checkbox .checkmark {
  display: inline-block;
  width: 20px;
  height: 20px;
  background-color: #eee;
  margin-right: 10px;
  position: relative;
  top: 2px;
}

/* On mouse-over, add a grey background color */
.custom-checkbox:hover input ~ .checkmark {
  background-color: #ccc;
}

/* When the checkbox is checked, add a blue background */
.custom-checkbox input:checked ~ .checkmark {
  background-color: #2196F3;
}

/* Create the checkmark/indicator (hidden when not checked) */
.custom-checkbox .checkmark:after {
  content: "";
  position: absolute;
  display: none;
}

/* Show the checkmark when checked */
.custom-checkbox input:checked ~ .checkmark:after {
  display: block;
}

/* Style the checkmark/indicator */
.custom-checkbox .checkmark:after {
  left: 7px;
  top: 3px;
  width: 5px;
  height: 10px;
  border: solid white;
  border-width: 0 3px 3px 0;
  -webkit-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  transform: rotate(45deg);
}