Deleting space above footer

Looks like a css fix.

What code would it need to fix it?

It look like it’s coming from the tags below, in line 314:

#main {
background: url(“../images/bg-main-r.jpg”) no-repeat scroll right top #FFFFFF;
border-top: 1px solid #FFFFFF;
min-height: 700px;
}

Link to the style:https://www.designandprintcentre.net/wp-content/themes/mystique/css/core.css

Where abouts do i place this code?