Need CSS Menu Help

So, I’ve been playing around with the color changing in the backend, and it keeps on modifying different parts that aren’t working out too well for me, and I think I’m getting confused.
I just want to change the color of the menu bar, but every time I do a few things happen: The bar stretches across screen with one color or no color changes happen at all.
I’m so not a css coder…but I know how to pick somethings apart and I was going by example in the css color changer…and I’m just getting lost.
Is there a code to enter to change menu bar section only to 1 color, and have the hover color different? I’ve seen a ton of examples…and yeah…I just don’t know. Help? Maybe? Drop a few bread crumbs? lol.
Here’s the site I’m working on:
https://christmasdealsandsteals.com

Thank you for any help! 🙂