How can I reduce excess white space under banners on my Debut theme homepage?

Hello,

I am on the Debut theme for about a month now. I finally got it looking like i want it. I am told that white space is good on home pages, to “let the eye rest”. Okay, but not too much. And, I think I have too much under 2 custom content headers that I have made into banners. See the banners above and below the video on the homepage of WorkoutSandbags.com. So, what code do i paste into the html, and where do I post it? I want to reduce the excess white space below the banner, to where it is the same as the white space above the banner. Also, I have been referred to the THEME.SCSS file before, but all i see is the THEMES.CSS file. is this the same file, and does it do the same thing?

Thank you Dale

@workoutsandbags - it is multiple changes, custom css and you have cuatom html in 2 sections which is black but taking some space