IOS端的checkbox有黑线

给checkbox加 appearance: none;

.checkbox{
  position: absolute;
  top:8px;
  right:3%; width:25px;height: 25px;
  background-color: #fff;
  border:1px solid #c1caca;
  appearance: none;
  -webkit-appearance:none;
  border-radius: 5px;
  box-shadow: 0 1px 2px rgba(0,0,0,0.1),
  inset 0 -4px 5px -3px rgba(0,0,0,0.2);
}

.checkbox:checked{
  background-color: #ecf2f7;
  border:1px solid #92A1AC;
  color:#243441;
}

.checkbox:checked:after{
  content: '\2714';
  position: absolute;
  top:0;
  left:0;
  color:#758794;
  width:100%;
  text-align: center;
  font-size:21px;
  line-height:24px;
  padding:0;
  vertical-align:top;

}