Muhammed I can help you with that, as I use it myself.
First, extract your font awesome pro files into your chosen directory.
You should be able to use this in the custom header. I created a folder in the root called "fontawesome" (very imaginative, of course 🙂), then applied the below
<style>
@font-face {
font-family: 'Open Sans';
font-style: normal;
font-weight: 300;
src: local('fontawesome'),
url('/fonts/open-sans-v17-latin-300.woff2'),
url('/fonts/open-sans-v17-latin-300.woff');
}
@font-face {
font-family: 'Open Sans';
font-style: normal;
font-weight: 400;
src: local('fontawesome'),
url('/fonts/open-sans-v16-latin-regular.woff2'),
url('/fonts/open-sans-v16-latin-regular.woff');
}
@font-face {
font-family: 'Open Sans';
font-style: italic;
font-weight: 400;
src: local('fontawesome'),
url('/fonts/open-sans-v16-latin-italic.woff2'),
url('/fonts/open-sans-v16-latin-italic.woff');
}
@font-face {
font-family: 'Open Sans';
font-style: normal;
font-weight: 600;
src: local('fontawesome'),
url('/fonts/open-sans-v16-latin-600.woff2'),
url('/fonts/open-sans-v16-latin-600.woff');
}
@font-face {
font-family: 'Open Sans';
font-style: italic;
font-weight: 600;
src: local('fontawesome'),
url('/fonts/open-sans-v16-latin-600italic.woff2'),
url('/fonts/open-sans-v16-latin-600italic.woff');
}
@font-face {
font-family: 'Open Sans';
font-style: normal;
font-weight: 700;
src: local('fontawesome'),
url('/fonts/open-sans-v16-latin-700.woff2'),
url('/fonts/open-sans-v16-latin-700.woff');
}
</style>
<link href="/fontawesome/css/all.css" rel="stylesheet"> <!--load all styles -->
The cumbersome part of this is that you then need to go through the CSS of the flarum site you have, and change the references to Font Awesome free like the below examples
.fa, .fas {
font-family: 'Font Awesome 5 Pro';
font-weight: 400 !important;
}
And
.item-discussion-views:before {
font-family: 'Font Awesome 5 Pro';
}
Not insurmountable if you use find/replace, but be prepared for lots of things to appear "broken" when you clear the cache. Overall, this took me about 2 hours to work through.
