Color of font in preview different from result Dawn theme

Hi everyone!

I’ve just started using Ghost and am using the Dawn Theme for my blog. When am writing the post and see the preview in the editor, the font is quite dark and very visible on the white background, which is great.

However, when I publish the post, the headings in the post turn into a lighter gray kind of color which is hard to see on the white background!

Any ideas on how I might fix this mismatch?