<button> elements don't inherit font-family from parent by default
in all browsers, causing a visible font mismatch between the
link-based buttons (Back To Store, Back To Website, Cancel Order)
and the button-tag-based Save Changes button on the order
confirmation page.
Add `font-family: inherit` to the base `.button, button` rule so
all button elements use the inherited page font (Roboto). Remove the
now-redundant `font-family: $body-font` from the `.primary` rule.
Fixes#13688
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>