This is Responsive Classic, the template Zen Cart itself ships with 2.2.2, shown exactly as it arrives. It is here as a point of reference – no contrast work has been applied to it, so please do not read it as an accessible example.
The accessibility comparison is on the two ZCA Bootstrap templates, each listed twice in View Different Templates: once as its author ships it, once with contrast corrections. Switch between a pair to see the difference, and see what this demonstrates.
