Div container overflow problems with Safari

On my Website Homepage I inserted a horizontal grey strip containing social network links. I want it to go all the way to the edges of the page like my footer does.

This is the code I used;

.outer {
float: left;
width: 100%;
height: 80px;
background-color: #f8f8f8;
margin-left: -178px;
padding-right: 349px;
position: relative;
}

At the moment this causes side-scroll to appear in safari and when zooming out it detaches from the edges of the page.