Side bar widget - font-weight and background image?

Hey guys, I just have a few questions. I'm editing the "LISTS INSIDE OF WIDGETS" on my css stylesheet. I was able to change the color of the font and center it. However, when i use

font-weight: 900; or
font-weight: bold;

there are no changes in my list. Am I doing something wrong or putting it in the wrong place?

My other question is, I have a background image for my Page widget. However it repeats itself as the sidebar gets larger. Is there a way to not have it repeat?

Thanks for all the help