I use the positioning, and margin css in conjunction with @screen size in certain bootstrap layouts to fine tune the layout on the smaller screens. Boot strap is not really that complicated once you understand how it works. the col css goes inside row css that is inside a container div. the container is usually fixed. with a fixed width, with a little padding, some people use the container-fluid on the outside and that is not really the way it supposed to be programmed. each section is supposed to be in fixed containers (brand, nav, container. footer) because they set:
"width=@screensize" instead of "width=100%
in fixed containers.
the row tag defines the row, the default size relation, of colums per row are set with this css set, by default its 12 column units, but you can change that, by compiling your own bootstrap source on thier website.
col-* css is just fixed heights and different padding whether they are xs, sm md lg or xl
hopefully that will help you understand bootstrap better.
oh btw the code in equalizer js is very similar bootstrap.js