Hi everyone, newbie TW user here 
One of my wikis will be public-facing, so while looking around at customisations I decided to try Giffmex’s “share button”. Unfortunately, as a duplicate of the permalink button, it’s redundant and adds clutter to the “more” dropdown (and Giffmex’s icon has a white background, no good as I’m using a dark theme). I thought it’d make more sense to just change the original button’s icon.
I’ve imported a new icon from https://morosanuae.github.io/tw-icons/, and (after some searching and fiddling!) replacing the contents of $:/core/images/permalink-button seems to have worked fine. The only problem is the icon is now black, so I presume something else needs changing to match the other buttons.
I’m at that toe-dipping point of proficiency where recognising HTML, CSS etc on sight is fine and I can make basic changes when it’s obvious what they would do, but anything more is too complex - so TW is a bit like the deep end of the pool 
Where should I be looking to make this edit? Or, alternatively, is there a simpler/cleaner method to changing the button icon?
