lhk on "[Theme: Encounters Lite] Changing the Showcase CSS/Menu Problem"

Illustration of the problem

I'm trying to change the way the showcase area displays. # 3 is what I would love to achieve (well, actually I'd love me a real drop shadow, but I'd be satisfied with this).

Version 1 is how it looks like with just the inner borders and margins set to 0px.

So I fiddled with the CSS and a child theme and pasted this into the child style.css:

#showcase {
margin: 0% auto;
padding: 1% 5%;
}

#showcase-wrapper,
#banner-wrapper,
#wpheader-wrapper {
	border-bottom: 8px solid #000000;
	border-top: 1px solid #000000;
}

and #2 is the result. I did try to set

#header {
border-bottom:9px solid #938E87;
}

but this doesn't change anything. At all.

Please, any ideas anyone what I could do? And I don't know whether I didn't break anything with the changes I made, especially the one from 1% to 0% or whether that was correctly done at all. Please advise there as well. Thank you so much!