Problema responsive left menu e background

[Prill]

prova a eliminare quel max-width impostato in

@media only screen and (min-width: 769px) {

.gridContainer {
	width: 88.5%;
	max-width: 1232px;
	padding-left: 0.75%;
	padding-right: 0.75%;
	margin: auto;
	clear: none;
	float: none;
	margin-left: auto;
}