Sidebar Formatting and Spacing

I’m adding widgets to my sidebar and can’t figure out how to make the spacing look correct. (View sidebar here: https://test.leighannmarquiss.com/blog-classic) The spacing between the widget title and the widget content is rather large, to the point where you can’t tell if the content is associated with the title above it or below it. I manually put the “Subscribe” title as a heading in the text block so that they were close enough, but if I want to use the Categories and Archives widgets, I can’t manipulate their title like that, the content is really far away from title? How can I tighten up this line spacing so that it’s clear what content is associated with the title above it?

Also, because my background is white (and I want it that way) the search bar is rather hard to see and I’d like to have a border around it (like the subscribe fields above it). How can I make that input box have a border?