Font-awesome in WordPress

Forums: 

I have interactive book with image hotspots as page content. I have custom hp5 css file which I use to modify css and it works as expected. I want to use font-awesome in css but the characters are not showing, instead there is a blue placeholder type graphic.This works in the rest of the WordPress website.

What can I do to show font-awesome characters?

Could it be that it's an older Font Awesome version and it can't recognise the code? If so, can it be updated?

H5P shows that Font Awesome (4.5.4) version is in use with 13 libraries and 3 content items.

This is my css:

.h5p-image-hotspot-popup-body ul li::before{
    font-family: 'FontAwesome';
    content: '\f00c';
    position: relative;
    margin-right: 10px;
    font-size: 100%;
    color: #3487df;
}

Thank you.

 

Content types: