重置 radio 和 checkbox 的样式

代码：

<!doctype html>
<html>

    <head>
        <meta charset="utf-8">
        <title>选择框样式</title>
        <style>
            label {
                font-size: 12px;
                cursor: pointer;
            }

            label i {
                font-size: 12px;
                font-style: normal;
                display: inline-block;
                width: 12px;
                height: 12px;
                text-align: center;
                line-height: 12px;
                color: #fff;
                vertical-align: middle;
                margin: -2px 2px 1px 0px;
                border: #2489c5 1px solid;
            }

            input[type="checkbox"],
            input[type="radio"] {
                display: none;
            }

            input[type="radio"]+ i {
                border-radius: 7px;
            }

            input[type="checkbox"]:checked+ i,
            input[type="radio"]:checked+ i {
                background: #2489c5;
            }

            input[type="checkbox"]:disabled+ i,
            input[type="radio"]:disabled+ i {
                border-color: #ccc;
            }

            input[type="checkbox"]:checked:disabled+ i,
            input[type="radio"]:checked:disabled+ i {
                background: #ccc;
            }
        </style>
    </head>

    <body>
        <label><input type="checkbox"><i>✓</i>复选框</label><br>
        <label><input type="checkbox" checked><i>✓</i>复选框</label><br>
        <label><input type="checkbox" disabled><i>✓</i>复选框禁用</label><br>
        <label><input type="checkbox" disabled checked><i>✓</i>复选框禁用已选</label><br>
        <label><input type="radio" name="abc"><i>✓</i>单选框</label><br>
        <label><input type="radio" name="abc" checked><i>✓</i>单选框</label><br>
        <label><input type="radio" name="abc" disabled><i>✓</i>单选框禁用</label><br>
        <label><input type="radio" name="def" disabled checked><i>✓</i>单选框禁用已选</label><br>
    </body>

</html>

效果：