How do I have diff bckgrd color for entries, how to go from photoshop to live?f

Hi guys, I want to create my own theme and as expected, am running into obstacles. I have some general questions I hope you guys can help me with.

I was going through this tutorial https://themetation.com/how-to-create-wordpress-themes-from-scratch-part-1/ as well as other similar tutorials on Youtube…

and I liked the idea of designing the page in Photoshop, but I wasn’t able to find how to use that design in the actual theme. What I mean is that I get that you can design the header and the footer, and match up the colours real nice, but how do you stylize the “featured post” and your entries in that way? Isn’t that purely CSS? I.E. that your post is x number of pixels from the left side etc. How do you have a stylized “read more” button like in the tutorial?

The main thing I want to do is have the backgrounds of my posts of a different colour than the background, and if possible, I’d like my post to have a border, glossy web 2.0 style, with some nice glossy buttons integrated (like read more and de.icio.us), more or less like in the tutorial link I have above. I originally wanted to customize a theme I downloaded to have this look, but I couldn’t figure it out. Any help here would be appreciated!