Have a look at all the pages and buttons etc.
Its the heights and padding that seem to be clashing.
As you will see in the custom css, i have added in !important to try rectify, so if some pages look correct, its because i have tried in the custom css in the admin, but its across all the pages.
you will see it
on the add to cart button and the scale up button for the image and on the reviews tab below that has the product tags.