Checkout screen on mobile devices severely broken

What needed to be done here is to bring responsive table to the theme.
I've found one library which aims to do it :
http://www.zurb.com/playground/playground/responsive-tables/

https://code.drupalcommerce.org/233

Need some more cleaup, but the essential work is here and working.

Next steps will be to review the user account order part, (which is still table)
for example, just after completing an order: http://cl.ly/image/0r2U2i1D3y13

Make sure you checkout http://nav.d8mux.org/

And the issues/discussions on it at http://groups.drupal.org/node/232653 and #1276908: Administrative tables are too wide for smaller screens

I reviewed these pages again. These pages have been significantly improved since this issue was created, so marking this as fixed.