Bootstrap is great, but it doesn’t have support for specifying border widths out of the box. The class border-left-0, border-top-0, etc, seem like they should work to specify a width… but they are for hiding specific portions of the border instead. This didn’t really make sense to me – after all, a border with a width of 0 would be hidden.
Luckily, if you’re using SASS, you can just add that in and use some existing pre-defined variables, too: