@blueprintjs/core/src/components/forms/file-upload.md

Core styles & components

@# File upload

Use the standard `input type="file"` along with a `span` with class `pt-file-upload-input`.
Wrap that all in a `label` with class `pt-file-upload`.

<div class="pt-callout pt-intent-warning pt-icon-warning-sign">
    <h5>Static file name</h5>
    File name does not update on file selection. To get this behavior,
    you must implement it separately in JS.
</div>

@css pt-file-upload