Website Design System Projects & Code Cheat Sheet

I finished the project Website Design System, I would like to know if I missed something in the code. I couldn’t center in the middle the text inside the color boxes, really don’t know why, I tried with display flex and text-align but nothing changes for better.
Here are the links to code if you want to take a look: >> My Website Style Guide

And the previous project, the Code Cheat Sheet: >> Project Cheat Sheet for Codecademy

Thanks!! :grinning_face_with_smiling_eyes: