healthchecks/static/css/checkbox.css

/* Customize the label (the container) */
.checkbox-container {
  display: block;
  position: relative;
  padding-left: 30px;
  margin-left: 20px;
  margin-bottom: 12px;
  cursor: pointer;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  font-weight: normal;
}

/* Hide the browser's default checkbox */
.checkbox-container input {
  position: absolute;
  opacity: 0;
}

/* Create a custom checkbox */
.checkmark {
  position: absolute;
  top: 0;
  left: 0;
  height: 20px;
  width: 20px;
  border-radius: 3px;
  border: 1px solid #DDD;
}

/* On mouse-over tint the border */
.checkmark:hover {
    border-color: #5db4ea;
}

/* When the checkbox is checked, add a colored background */
.checkbox-container input:checked ~ .checkmark {
  border-color: #0091EA;
  background-color: #0091EA;
}

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

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

/* Style the checkmark/indicator */
.checkbox-container .checkmark:after {
  left: 7px;
  top: 3px;
  width: 5px;
  height: 10px;
  border: solid white;
  border-width: 0 2px 2px 0;
  -webkit-transform: rotate(45deg);
  -ms-transform: rotate(45deg);
  transform: rotate(45deg);
}