What's Riot's Stance on Vanity Mods?

For example: let's say I wanted the hud to be in a red color scheme compared to the dark blue-ish it is right now, or maybe have a custom skin or something? The following things don't add a kind of timer and/or game breaking bug, so is it alright to play with fan mods like this? I love the website Mapskins.com but I am always afraid to try their stuff because I really would prefer to not be banned. Someone send a link if they have said stuff about this before, or heck a Rioter themselves could fill me in too which would be nice.