To reduce widget padding / enlarge body content

My website is in maintenance mode so I can’t link you to it, but I’m using the free theme “Custom” which has a parent theme of “Omega”.

Three things:

– On the main page I’d very much like to reduce size of the padding around the sidebar and increase the main content body. I’ve tried inputting many things to .CSS editor, nothing works. My attempt to decrease space in between widgets DID work, with `.sidebar .widget {
margin-bottom: -5px !important;
}`

– On posts, I’ve removed the widget sidebar (which I can’t reverse apparently but that’s fine,) but now I have big white space where the sidebar was, with content crammed all against the left side. I’d like to center it and fill out the page.

– I’d also like to know how to change the body background colour of one single page to black.

I’ve spent the day on all three of these to no avail. It seems my theme is stubborn, it is beyond my comprehension. Any help much appreciated.

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