custom css not working?

Hi, first thanks to this nice plugin. I would like to add custom css in order to give the qib-container a margin-right and then define negative margin on the add to cart button. The reason is, that if a product has only 1 quantity, the add to cart is not fully to the left. Maybe a WP/WC topic. However, I cannot have CSS applied to the qib-container, even with !important. Thx, Michael