how to devide login page into two structured layout and want to make it resposnisve

Hi i am using dublin theme. and i want to devide login page into two structured layout. which should be responsive. left bax having some logo and info and it looks good on desktop but if i use .tablet and .phone class which are not working .this is my login page which is available in common-> login

You can use Structure/Columns  2 and set different  behavior for phone and tablet

i use structured column two and also set behaviour for tablet and phone. but it is not working. is there any isuue while using structured column two in login page? because on normal page it is working but only on login page it is not working.

Try change layout web block on login screen as it differs from other pages: