Button styling

Martycz

Hi,

I would like to edit radius of my button to 0px but I can't figure out how. I read on this forum that radius for buttons cannot be changed with shortcodes. 

Therefore I tried to upload the following css into theme option/custom css:

.btn {

border-radius:0px !important;

}

This is however not working for me. 

Also I wanted to add hover background with css, as that's also not possible with shorcode

btn:hover {
background: transparent !important;

                  border:2px solid white  !important;

}

Unfortunately this is also not working for me.

Could you please help me
thanks