Improve grid view in smaller screen

Fixes

Fixes the grid style in smaller screens.

Type of feature

This PR is for a minor improvement on an existing feature.

Description

I was browsing Paulina's website on my small smartphone the other day and noticed that the grid style was a bit off (check screen recording #1).

I have made a very small edit in the countries.html to fix it adding d-flex class to each div with a class of col (i.e. each grid element containing the country flag, name, and pma info).

It looks much better in my opinion.

Screen recordings

#1 - Before	#2 - After
before-fix.mp4	after-fix.mp4