How to change the size of the file upload field, when multiple option is enabled?

"The workaround is to enable a Multiple Files option"

Well yes I can see that. I have two questions related to that:

 - As the button is totally changed when choosing "multiply", what is the css for changing size?  

You can add this CSS code to your form to change the size of the upload button:

.qq-upload-button {

    width: 100px!important;

    height: 20px!important;

    padding: 0!important;

}

How to Inject Custom CSS Codes

Here is my demo form: https://form.jotform.com/80184196446967 

Feel free to test it and clone it.