First, I added it in using “custom css manager” plugin. When that didn’t work, I went into main.css (the theme’s author’s version of style.css) and replaced this code:
.filterable {
float: right;
list-style: none;
text-transform: uppercase;
margin: 0 0 5% 0;
clear: both;
}
I switched it back afterwards out of fear it’d affect something else.