文件上传按钮样式定制

<!DOCTYPE html>
<html lang="zh">

    <head>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <meta http-equiv="X-UA-Compatible" content="ie=edge" />
        <title>input file 样式更改</title>
        <style>
            * {
                padding: 0;
                margin: 0;
            }
            
            .uploadImg {
                display: inline-block;
                /*相对定位*/
                position: relative;
                width: 140px;
                font-size: 16px;
                color: #007fcb;
                margin-top: 10px;
                overflow: hidden;
            }
            
            .file {
                /*绝对定位*/
                position: absolute;
                z-index: 100;
                /*透明度为0-------关键设置*/
                opacity: 0;
                filter: alpha(opacity=0);
                width: 140px;
                cursor: pointer;
            }
            
            .uploadImg a {
                font-size: 16px;
                color: #007fcb;
            }
        </style>
    </head>

    <body>
        <span class="uploadImg">
            <input type="file" class="file" size="1" >
            <a href="#">上传图片</a> 
        </span>
    </body>

</html>
效果：