Remove space/padding from nav-menu in TwentyTwelve

Hello,
I’d like to remove the bottom space between my nav-menu and my header image. I’m doing a few tweaks, trying to make more content “above the fold”.
My site is: https://studyathomemama.ca/
My theme is TwentyTwelve

I’d also like to remove the “leave a reply” link that follows my title on my post previews, to bring the content closer to the title.

Thanks for any insights!