[color=royalblue]@Denis_Frosty_Andreyc[/color] is experiencing issues with Font Awesome icons not displaying correctly in the nav. [color=royalblue]@Johani[/color] suggests adding font: normal normal normal 14px/1 FontAwesome; to the mixin to fix the issue.
After implementing the fix, [color=royalblue]@Denis_Frosty_Andreyc[/color] encounters another problem where the icon is displayed outside the frame. [color=royalblue]@Johani[/color] advises using a.tag-official instead of .tag-official to target only links inside the list, and adds a margin-right: 5px to move the icon inside the frame.
Instead of using .tag-official try using a.tag-official to only apply the styles to links inside the list and not on list items if they also share the class.