Different widths on a flex items of same class

HTML-CSS
#1

Tell us what’s happening:
Trying to do the product landing page where it displays the font-awesome icons.

I am trying to understand WHY setting width on flex items results in different width for the same class. But if I set the width for the tag within the flex item the width works as expected.

Your code so far

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:75.0) Gecko/20100101 Firefox/75.0.

Challenge: Build a Product Landing Page

Link to the challenge:

#2