Changing Whitespace defaults

Hello All,

I have searched for sometime but cannot figure out how to change 4 things in the Whitespace template.

1. Remove the black lines that appear when hovering over a link in the menu.

2. Remove the transparency of the menu bar, my boss would like to turn it into a solid white bar.

3. Remove the black lined page breaks

4. Change the neon green color that appears at the top of the browser window when scrolling down.

I assume these are all issues I can change in CSS, but I cannot find where they are hiding let alone what code to use to make what I want to happen, happen! Please help! Thanks!