This is how rendering looks:
Code:
<span class="addtocart-button">
<input type="submit" name="addtocart" class="addtocart-button" value="Add to Cart" title="Add to Cart">
</span>
so add your css overrides at bottom of templates/hot_ecommerce/css/vm_ecommerce.css
use !important flag for properties you set like:
.addtocart-button INPUT{
width:120px!important;
}
