.collapsible-header{
	background-color: transparent;
}

.f {
	width: 60%;
	margin: 0 auto;
}

@media only screen and (max-width: 992px) {

	.f {
		width: 70%;
		margin: 0 auto;
	}

}

@media only screen and (max-width: 600px) {
 
	.f {
		width: 80%;
		margin: 0 auto;
	}

}