CSS怎样修改单选框和复选框的样式

input[type=radio]{
    height: 0.28rem;
    width: 0.28rem;
    vertical-align: middle;
    margin-left: 0.1rem;
    background-color: transparent;    
    -webkit-appearance: none;
    border-radius: 50%;
    position: relative;
}
input[type=radio]:checked:before{
    content: "";
    display: inline-block;
    height: 0.32rem;
    width: 0.32rem;
    background: url(../images/checked.png) no-repeat;
    background-size: 100% 100%;
    border-radius: 50%;
    position: absolute;
    top: -0.04rem;
    left: -0.04rem;
}

input[type=checkbox]{
    height: 0.28rem;
    width: 0.28rem;
    border: 1px solid #c3c3c3;
    background-color: transparent;    
    -webkit-appearance: none;
    position: relative;
    border-radius: 0.04rem;
}
input[type=checkbox]:checked:before{
    content: "";
    display: inline-block;
    height: 0.3rem;
    width: 0.3rem;
    background: url(../images/checked2.png) no-repeat;
    background-size: 100% 100%;
    position: absolute;
    top: -0.04rem;
    left: -0.04rem;
}