Why can't I change the point size of the excerpt in a summary block?

I have set up summary blocks on a home page to pull blog posts. I used custom CSS on the summary block, because I couldn't get "Assign styles" in the Fonts section to adjust the summary block.

All parts of the summary block have responded to custom CSS excerpt for the summary excerpt. I can change the font, style, and padding around the excerpt, but I cannot adjust the point size.

Any ideas why the point size won't change?

Thanks!

It did work! Thank you so much!

@JDED Yay! Happy designing 😊