Buttons are build using Foundation. Basic styles are available when developing custom HTML to handle variations with brand consistency. See http://foundation.zurb.com/docs/v/4.3.2/components/buttons.html for more details.
Default button styling provided by Foundation configuration.
<a class="button">Default button styling with the .expand class applied to make the button fill its grid column. Primarily used for creating mobile-friendly full-width buttons.
<a class="button expand">(Additional button styles not provided by Foundation)
<a class="button tertiary">(not provided by Foundation)
<a class="button primary alt-1">Exetended from base Foundation expanded buttons to include indicator icons.
<a class="button more">