[Theme: Avada] Can't edit certain div on website

I have a job to make some changes on this website, and the last one that looked easiest, I can’t seem to figure it out. The page is http://www.thinknowresearch.com/about/ , and I have to edit this div where it says “About us”, to make its background white. I have found that div is “.page-title-container”, and I have found it in style.css, deleted old background color (#f2f2f2) and made new one white. I saved it, but again it is the same color, when I inspect element in my browser, as you can see it, on the line 1597, there is:
.page-title-container{
background-color:#f2f2f2;
}

What am I missing here?
Thanks