上传文件input（type=file）美化。

input file 把之前的按钮透明度opacity设置为0，外层用div包裹。

1 <div class="uploadButDiv greenButton text-center">2 <input type="file" accept="image/jpeg,image/jpg,image/png,image/gif"/>上传4 </div>

.uploadButDiv {width: 100%;height: 3.25rem;line-height: 3.2rem;position: relative;cursor: pointer;color: #0057FF;font-size: 1.125rem;background: #fff;border: 1px solid #0057FF;border-radius: 4px;overflow: hidden;display: inline-block;}.uploadButDiv input {width: 100%;position: absolute;right: 0;top: 0;opacity: 0;cursor: pointer}