Friends, Romans, CitiZENS, lend me your ears ... and a few kind words of advice.

I am using v1.3.8, modifying the classic template (good place to start when you dont know where to start).

In my categories sidebox, if I select a major category the sub categories are listed below it (fantastic). However there are "bullet points" (what is the actual term?) that look like this "|_".

e.g., in ascii art style I have

Bicycles->
|_BMX
|_MTB
|_Road

Where / How can I change the red bits?

I am not sure what this is actually called and so I havent had much luck searching. Could someone please help!

Thank you in advance.
Daniel