Joomla 3.3.3 and VM 2.9.9b, see http://testvm.kurtmeyer.com/products/ornaments-and-magnets/friendship-stars.html, the add-to-cart quantity input box is too narrow, but that's not apparent until you increase the number from 1. A double-digit number such as "10" is almost completely hidden.
Is fine for me with VM2.9.9c with Protostar template on J3.3.4
[attachment cleanup by admin]
the padding in vm-ltr-site could do with an !important
the template.css is overwriting it - after 9 the number is pushed behind the outline
input.quantity-input {
font-weight: 700;
height: 2.2em !important;
margin-bottom: 0 !important;
padding: 0.1em !important;
text-align: center;
width: 2.2em !important;
}