Colour of vote button

My vote button is light grey and you cannot really see it. I need to change the colour. I read in another of your answers what to do and I did this:

Editing wp-polls/polls-css.css (inactive) – Went there
and put my colour code in

}
.wp-polls .Buttons {
border:1px solid #1A2A6A;
background-color: #1A2A6A;

But it has not changed anything.

Can you suggest what else to do?

Thanks,

https://www.ads-software.com/plugins/wp-polls/