Multilevel tags

[sylvaine]

Is there any way to get my tags to show up multilevel in the sidebar of my journal, the way they show up on my tags page? So instead of having

fandom
fandom:Harry Potter
fandom:Sherlock

it would show up as

fandom
             Harry Potter
             Sherlock.

I have absolutely no clue about CSS and the like, so please use really easy language. /o\

Thanks a lot in advance!