🌟Responsive Testimonial grid section made using HTML & vanilla CSS 🌟

Your project looks absolutely awesome. Congrats for finishing this challenge, I hope you enjoyed your time while doing this.

There is no problem in using column-start/column-end or row-start/row-end. This all comes down to preference, grid-template-areas is just a shorthand for writing column/row-start/end for shorter code, if you feel more comfortable and maybe you find it easier to read column/row-start/end, then go for it.

Overall, your code looks all good to me, I can suggest to maybe remove margin: 6rem auto auto for your testimonial.container, just so the container is centered. Nicely done!

grid-template-areas are best you don't have to do a lot of works, just give it a name and give those names to the individual cards, I used that too.