Tabs are made of two objects: a dl object containing the tabs themselves, and a ul object containing the tab content.
If you want your tabs to run the full width of their container evenly, you can add class of .two-up, .three-up, .four-up, and .five-up to them.
Contained tabs have a simple added class of "contained" on the tabs-content element. What that means is the tab content has a border around it tying it to the tabs. You can still use standard column sizes inside a tab element.
If you need an alternate view for tabs (especially for filters, or similar), you can use pill-style tabs. They look like this:
If you want a standard, horizontal tab group to act vertical on small devices, adding a class of "mobile" to a standard (not vertical) tab group will switch them to full width nav bars on small screens.