Cannot make Nimble font sizes and spacing same as non-Nimble pages

I am experimenting with making background images on Nimble Builder pages. I have replicated my About page (https://tuxboy.net/about/) built with the regular WP editor, to a page built with Nimble (https://tuxboy.net/aa-sandbox/).

Is there an easy way to make the headings and font sizes in a page built Nimble the same as a page built with WP without much difficulty? I have tried changing font sizes, line spacing, heading sizes, etc. but it is not easy to make these two pages look the same.

I would like consistency in style whether the page was built with Nimble or the WP editor.

The page I need help with: [log in to see the link]