Long Button instead of Square Button

My variation name is long, when I try using the button / select, it looks very bad because the long variation name is squeezed into a square box.

I want the button to be a long rectangle button, and arranged vertically, like this website:
https://ownkoti.com/products/suede-pure-color-stretchable-couch-cover
Look at the “Size” variation attribute.

Mine is:
Squeezed into a square box with long variation name inside
Arranged the box from left to right (instead of vertical arrangement like the example above)

Please help thank you