checkbox默认样式修改

html部分

 <label><input type="checkbox">身份证</label>

css部分

使用伪类元素对checkbox样式进行修改

边框样式在before中修改，"\2713"为字符表勾选字符

input[type="checkbox"] {
    width: 20px;
    height: 20px;
    display: inline-block;
    text-align: center;
    vertical-align: middle;
    line-height: 18px;
    margin-right: 10px;
    position: relative;
}

input[type="checkbox"]::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    background: #fff;
    width: 100%;
    height: 100%;
    border: 1px solid #d9d9d9;
    border-radius: 4px;
}

input[type="checkbox"]:checked::before {
    content: "\2713";
    background-color: #fff;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    border: 1px solid #7D7D7D;
    border-radius:4px;
    color: #7D7D7D;
    font-size: 20px;
    font-weight: bold;
}