I've searched for a bit and I haven't found a solution to my liking: I want to avoid adding more modules to the project.
I'm very new to Drupal, so I have minimal knowledge on that matter. I have this project which somebody else has made. They created a module which adds a menu item on the Administration menu. What this module doesn't do, is add an icon to the menu item, which makes it look bare.
I want to add a custom icon I've made next to the menu item text. The reason it needs to be a custom icon and can't be fontawesome (or anything of its liking), is because it has to be a variation of the site logo.
Is there a way to accomplish this without adding more modules to the project, or is adding more modules the only way?
It's Drupal 8 with Lightning on Debian 9 with Apache2.4 and PHP7.2.