Ok so the issue is we have the demo running at 975px width and you changed it to 1180px which is fine but you just need to adjust the below in your responsive.css file. Just look at the top for:
@media screen and (max-width: 1000px){
/* DEFAULT
----------------- */
.s5_wrap {
width:95% !important;
}
}
And change it to the below, you may have to increase this max width number but I'm estimating this should be around the number you'll need:
@media screen and (max-width: 1230px){
/* DEFAULT
----------------- */
.s5_wrap {
width:95% !important;
}
}