line between widget area and main content

Hey jelle,

Here is the code you can put in Enfold > General Styling > Quick Css,  if it does not work, put into themes/enfold/css/custom.css

//this will work only on the page you posted
body .container_wrap .avia-builder-el-last.avia-builder-el-3   {
    padding-left: 40px;
    border-left: 1px solid #ccc;
    margin-left: 20px;
}
//this can work on most pages
body .container_wrap .avia-builder-el-first.avia-builder-el-1   {
    padding-right: 40px;
    border-right: 1px solid #ccc;
}

If you need further assistance please let us know.
Best regards,
Victoria