How to make Promotion Headline and Featured Content background transparent?

Hi Support, I was wondering if you could tell me the CSS on How to make Promotion Headline and Featured Content background transparent? (currently white) I've tried a few CSS codes but doesn't look like any of them are taking effect. My site: http://tuanzbuild.tuanz.org.nz/ White area in "Welcome to TUANZ" and 'Featured Content' - I would like to make transparent/clear so it'll show the background image behind Cheers, Rob