html部分
<label><input type="checkbox">保存密码</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;
}
