Light and simple Reactjs drag and drop files library to use with very flexible options to change, so you put whatever the design you want for your drop-area. Users can drag and drop or even select the file anywhere in the window.
What I did to solve it was first to check the tags it contains in the inspector and then add the necessary colors through SCSS.
I've included screenshots below, hope it helps!
Have you tried this:
<FileUploader classes="dragging">
CSS: