Negative margin for featured image

I would like to have my featured image be under the navbar, which has a gradient fade to transparent.

I got this working by additional the following custom css:

/* Set header transparency and remove border */
#header-inner-bg {
	background: rgba(0,0,0,1);
	background: -moz-linear-gradient(top,rgba(0,0,0,1) 0%,rgba(255,255,255,0) 100%);
	background: -webkit-gradient(left top,left bottom,color-stop(0%,rgba(0,0,0,1)),color-stop(100%,rgba(255,255,255,0)));
	background: -webkit-linear-gradient(top,rgba(0,0,0,1) 0%,rgba(255,255,255,0) 100%);
	background: -o-linear-gradient(top,rgba(0,0,0,1) 0%,rgba(255,255,255,0) 100%);
	background: -ms-linear-gradient(top,rgba(0,0,0,1) 0%,rgba(255,255,255,0) 100%);
	background: linear-gradient(to bottom,rgba(0,0,0,1) 0%,rgba(255,255,255,0) 100%);
	filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#000000',endColorstr='#ffffff',GradientType=0);
	border-style: none !important;
}

#header-inner {
	border-style: none !important;
}

/* Move featured section under nav bar */
#slider-section {
	margin-top: -130px;
}

It works well, see here:
http://dev.genco.tv/home-carousel-3/

Unfortunately, it also affects pages that don’t have a featured section. See here:
http://dev.genco.tv/?s=oil

I don’t see a way to add an additional class to the featured section so I’m not sure how I can only target specific pages with a negative margin on the featured section.

Any help would be great.

Thanks,
Chris