input[type=checkbox] {
  width: 18px;
  height: 18px;
  margin-right: 5px !important;
  cursor: pointer;
  font-size: 13px;
  visibility: visible;
}

input[type=checkbox]:after {
  content: "\00A0"; 
  background-color: #fff;
  display: inline-block;
  padding-bottom: 5px;
  color: #fff;
  width: 20px;
  height: 20px;
  visibility: visible !important;
  border: 1px solid #7b7b7b;
  padding-left: 4px;
  border-radius: 5px;
}

input[type=checkbox]:checked:after {
  content: "\2714";
  padding: -5px;
  font-weight: bold;
  background-color: #003160;
  border: 1px solid #003160;
  color: #fff;
}