EntryWizard does set the background color for the headers in the upload form to grey (either black or white text should be visible), and sets black borders on a few items.
Otherwise it does not specify colors — this should be done by your theme. It does work with some dark themes, but each one can be different.
If you are willing to redo it with each upgrade, you can change the color for “.ewz_upload_table th” in css/entrywizard.css. But the colors on the dropdowns should be coming from your themes.
To see what is setting the color, in Chrome you can right-click on any item in the page, select “inspect” and see what is setting what color and other properties. Look for the file name (“entrywizard.css”, “style.css”, etc) associated with the “color” value for the item.
Many thanks for the reply and tips 🙂