Specify the number of files uploaded to the vault and change the style

Vault
#1

I want to limit the upload of only one file unconditionally.
How is it handled?

And I want to delete the “Drag & drop files or folders here or” that is gathered in the default background, move the “Browes files” button to the right, and set the vault height to 100px.
What should I do?

Please provide example source.

#2

You can control the number of the uploading files t your vault using the beforeAdd event:
https://docs.dhtmlx.com/vault/managing_files.html#controllingnumberofuploadedfiles
What for the vault look customization I can only suggest you use the CSS:
https://snippet.dhtmlx.com/uhxnv072