GeneratorPress Theme fonts and fontsize - header, links and body

Dear madam and sir,

I tried to make some changes with the fonts in the generatorpress theme and need some help, please.

1. is it possible to change the font and fontsize at the 'website information'?

2. how can I change (reduce) the fontsize of article names (blog, e.g. latest entries), article content and site content (incl Sitenames)?

Currently I solved this alone in the header via an image, instead of using an font.

Many thanks and kind regards

Joa