Thank you; that helps a lot! I found this list of icons called “Font Awesome”. Is si-map-pin a similar kind of thing? In other words, “si-headphones” would put a little headphone icon the way “fa-headphones” would?
OK; I figured out the little vertical bar part of it–it’s a setting under sidebars, “Sidebar Style: Title Focus”.
Still don’t understand what “Custom Lists” are . . .
