This site used HTML, CSS, and Bootstrap. It was an emulation of elements from this Bootstrap 2 site.
Here are the links that helped me:
I am getting much more comfortable with Bootstrap and adjusting the columns to make the site look nice at different sizes. I am starting to be able to look at a page and be able to guesstimate the column widths, but not the pixel sizes just yet. Also I am much better at searching for the CSS and Bootstrap terms to build and edit the pages.