I'm struggling to find the variables to how you can change the colouring of the hollow buttons that foundation provides. 

At the moment I have to override the styling by doing the below: 

```
&.hollow {
   border: 1px solid $clr-primary;
   color: $clr-primary;
}

```

I like having to do most of my styling changes in the foundation settings file instead of taking this approach so I don't have to write more CSS than I need. 

Is there a variable that I am missing that I can apply these stylings to in the foundation settings?