I got a website from HTML5UP to use as my portfolio. I am unable to figure out how to replace these icons that came prebuilt with the website. I don't mind using Font Awesome, I just do not know how to replace them as they aren't relevant.
For example:
<div class="col-4 col-6-medium col-12-small">
<section class="box style1">
<span class="icon featured fa-comments"></span>
<h3>Lean, Six Sigma, Kaizen, Kanban and 5S</h3>
<p>
Applicable to both software and industrial settings.
</p>
</section>
I want to replace that class="icon featured fa-comments" with another image. I tried searching FA for one, obtained the HTML for it <i class="fas fa-industry"></i> but when I replace it, the formatting isn't the same.
If i change it to class="icon featured fa-industry" it doesn't work. Neither does class="icon featured fas fa-industry" And if I use <i class="fas fa-industry"></i> the icon is printed without formatting
How can I change just the image? And keep the formatting.
EDIT: Below is a snippet of the main.css file if that helps



