Search bar transparency

Hi all,

I inserted a search bar on the navbar by using the steps on this link

http://docs.themeisle.com/article/78-zerif-adding-a-search-bar-in-the-top-menu

But it is a bright white box and I want to change it to transparent, is there a way to do this with some basic css?

My website isn’t live yet so no link sorry. But it’s the standard zerif lite theme.