Social Proof Section

Would like to know if my layout is good --- as well as all the questions below:

Was the use of clamp appropriate -- is this the best way to use this feature ? (line 122) I was aiming to have the h2 get slightly bigger as the screen grows. I believe this was achieved. Any feedback would be welcomed.

When you have a flexbox -- and you set gap to a percentage -- what is this percentage based on ? Is it based on the width of the parent element ?

I have used the picture element to change the different background images. I have used Kevin Powell's YouTube Short as the inspiration for this: https://www.youtube.com/shorts/d9i68C628Nk.

However, I have left px as the default unit on this. Should it be changed to rem or em ?