Replicate Edit mode text into Preview mode

Hi All,

Would anybody be able to help me replicate the style of text in the editor mode into the preview mode please?

The style of text in the editor mode is much easier on my eyes - its a lighter text if you see what I mean. When I toggle to preview mode its quite harsh.

I’ve searched the forum and found advice on how to do the opposite (make the edit mode text heavier) but can’t find anything in the opposite direction.

Thanks very much for any help,