使用CSS3美化复选框checkbox

方法一：使用图片

.checkbox {
    display: none;
}
.checkbox-i{
    margin-right: 20px;
    background-image: url("../img/icon.png");
    background-repeat: no-repeat;
    background-position: -324px -40px;
    width: 22px;
    height: 22px;
    display: inline-block;
    position: relative;
    top: 5px;
}

.checkbox:checked + .checkbox-i{
    background-position: -324px -11px;
}

<input type="checkbox" class="checkbox " id="test">
<label class="checkbox-i" for="test"></label>
<label class="label" for="test">

test

</label>

方法二：使用after

<html>
<head>
    <title>aa</title>
    <style>
        .chk_1 {
            display: none;}
        .chk_1 + label {
            background-color: #FFF;
            border: 1px solid #C1CACA;
            box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05), inset 0px -15px 10px -12px rgba(0, 0, 0, 0.05);
            padding: 9px;
            border-radius: 5px;
            display: inline-block;
            position: relative;
            margin-right: 30px;
        }
        .chk_1 + label:active {
            box-shadow: 0 1px 2px rgba(0,0,0,0.05), inset 0px 1px 3px rgba(0,0,0,0.1);
        }

        .chk_1:checked + label {
            background-color: #ECF2F7;
            border: 1px solid #92A1AC;
            box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05), inset 0px -15px 10px -12px rgba(0, 0, 0, 0.05), inset 15px 10px -12px rgba(255, 255, 255, 0.1);
            color: #243441;
        }

        .chk_1:checked + label:after {
            content: '2714';
            position: absolute;
            top: -7px;
            left: 0px;
            color: #758794;
            width: 100%;
            text-align: center;
            font-size: 1.4em;
            padding: 1px 0 0 0;
            vertical-align: text-top;
        }

    </style>
</head>
<body>
<input type="checkbox" id="checkbox_a2" class="chk_1" /><label for="checkbox_a2"></label>
</body>
<html>

label标签设置方框大小。