By popular demand, the Add to Cart button group can be optionally positioned fixed at the bottom of the page or here in the product details. You can change from Default to Fixed position at any screen resolution, same as with all the other 2000+ CSS options.
Tabs, accordion or all-visible blocks styles for your html content. Any module can be displayed inside the product page (Products, Sliders, Banners, Gallery, etc.) via the all powerful Blocks/Tabs position module, which is actually a page builder itself - crazy stuff :)