默认文件上传示例，多文件文件上传示例，小文件输入示例，大文件输入示例。
<div class="mb-3">
<label for="formFile" class="form-label">Default file input example</label>
<input class="form-control" type="file" id="formFile">
</div>
<div class="mb-3">
<label for="formFileMultiple" class="form-label">Multiple files input example</label>
<input class="form-control" type="file" id="formFileMultiple" multiple>
</div>
<div class="mb-3">
<label for="formFileDisabled" class="form-label">Disabled file input example</label>
<input class="form-control" type="file" id="formFileDisabled" disabled>
</div>
<div class="mb-3">
<label for="formFileSm" class="form-label">Small file input example</label>
<input class="form-control form-control-sm" id="formFileSm" type="file">
</div>
<div>
<label for="formFileLg" class="form-label">Large file input example</label>
<input class="form-control form-control-lg" id="formFileLg" type="file">
</div>
