How two I change size of font in blog?

Could you possible tell me how to change the size of the font in the blog in RW.
I have tried lots of ways but nothing is working for me at the moment. I am using the Square theme By Yuzool.
Any help would be gratefully appreciated.
Thank you

Maybe by this custom css:

.blog-entry-body {
font-size: 200%;

It depends on the theme. You put the custom code into the inspector area “Meta Tags & HTML” under “CSS”. The value (here 200%) you can change individually, it can be %, but also em or px.

Thank you very much. That worked!