Need Help Moving And Removing Things

Hello Everyone,
I’m fairly new to wordpress as far as having it hosted on my website goes and I’d really appreciate a little help regarding editing my blog. I decided to modify the Pixeled theme and if you go to my website https://www.planetofawesome.com, you’ll see the difference. I figured out how to move most of the content where I need it on the page myself using padding even though I’m not familiar with css. However, there are some problems I ran into. Firstly, my website displays nicely on internet explorer but strangely, not on firefox or opera. I tested it mainly on internet explorer because this was what I’ve understood to be the troubled browser out of the three.

That’s my first problem. My other problem is you’ll see when you click one of my categories on the menu bar up top ie. Tech, a bar shows up labeled tech. I’d like to either move this bar into line with the rest of my page or remove it completely. Any ideas on how?

My last problem is the smallest and I can afford for this to go unresolved but it’s preferable that it’s solved. The sidebar kind of intrudes on the content area in my blog. It’d be better if I could move it more to the side where it belongs. I’ve tried to do this using the padding technique but it really messes the way it appears so…?

Any help on these matters would be extremely appreciated. Thanks everybody.