You are using a theme correct? In my own site I just added a css file or you could use style tag to change the font size in your single.html. I was just looking at the academic git page man that thing is complicated! Following the suggestion It seems like they are suggesting you change the font size in the toml file? What have you done so far? There is apparently a font size and a font size small feature in each possible toml file. I’m guessing you could even create your own if you knew how. From what I can guess you can change the font style and size in the toml file your using under data/fonts/style your using(there are 3 different ones there. ) change that and see what happens.