Decrease font testimonial block

Can anyone help me with the right code? I want to decrease the fonts of the testimonial block on this page: https://www.riengriffioen.nl/home

I've tried a few codes which I've found on the forum but with no result. Many thanks in advanced!

Thank you so much Ziggy! A bit silly from me that I did not found this 😉

30 minutes ago, Bluemonque said:

Thank you so much Ziggy! A bit silly from me that I did not found this 😉

No worries, that's what the forum is for!