messing around in the console, i
think the empty space at the bottom was because you had too many rows in your grid-template! the rows in your grid are very tall, and your template specifies five of them -
grid-template-rows: repeat(5, 1fr);
but you've only used 3! so there are two empty rows in the grid that are super tall, creating empty space. setting the rows to 3 instead should fix it.
i have no idea what's going on with the winamp thing, it looks like it has a lot of fiddly bits going on in there and i wouldn't know where to start with it sorry! edit: oh, and the last.fm thingy doesn't appear at all for me, possibly because of one or more of my browser extensions, so idk about that either. double sorry!!