How to change the node-red editor font size and color

How to change the node-red editor font size and color , what is the css file name that I have to change. I have changed the theme but the header font color and size are still same.

If you use the developer tools in your browser you'll be able to identify the CSS class you need to override to provide a different size or colour to those elements. You can then add that to the custom CSS file you provide via editorTheme.