Testimonials Grid

The only issue I'm having is that this challenge looks different in Chrome versus Firefox. In Firefox, the "content-wrapper" container has all the grid items squished together. Using Dev Tools, it appears the issue may be with grid-template-columns. I don't know if I should add Mozilla-specific code, which I'm not familiar with so I have no idea of where to go with that, or could it be something else in my code that's affecting that? Feedback is welcome as always!

Here's my Code Pen too: https://codepen.io/imtheheppest/pen/oNEajab