修改radio默认样式

input[type="radio"]{
    width: 20px;
    height:20px;
    margin:0 4px 0 0;
    appearance:none;
    position:relative;
}

/*未被选中的样式*/
input[type="radio"]::before{
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    background: #fff;
    width: 100%;
    height: 100%;
    border: 1px solid #d9d9d9;
    border-radius: 4px;
}
/*选中的样式*/
input[type="radio"]:checked::before{
    content: "\2713"; /*2713表示选中*/
    background-color: #fff;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: 1px solid #7d7d7d;
    border-radius: 4px;
    color: #7d7d7d;
    font-size: 20px;
    font-weight: bold;
    text-align: center;
    line-height: 20px;
}