header {
	background-color: gray;
	height: 100px;
	width: 100%;
	border-radius: 30px;
	box-shadow: black 5px 10px;
	text-align: center;
	position: absolute;
	top: 0;
	transition: 0.3s;
}

header:hover {
	background-color: gray;
	font-size:25px;
}

.Head {
	position: relative;
	padding: 30px;
}

.exp {
	margin-top: 15%;
	margin-left:100px;
	background-color:black;
	width:10%;
	height:20%;
	padding:20px;
	color:silver;
	border-radius:30px;
}

a {
	color: black;
	text-decoration: none;
	margin: 20px;
	padding: 10px;
	transition: 0.3s;
}

a:link {
	color: black;
}

a:visited {
	color: aquamarine;
}

a:hover {
	background-color: silver;
	color: white;
	border-radius: 5px;
}

a:active {
	color: blue;
}

a:focus {
	color: red;
}

body {
	background-image: url("it.jpg");
	background-size: cover;      
	background-position: center;
	background-attachment: fixed;
	background-repeat: no-repeat;
	min-height: 100vh;
}


@media (max-width: 768px) {
	header {
		height: auto;
	}
	.Head {
		padding: 20px 10px;
		display: flex;
		justify-content: center;
		flex-wrap: wrap;
	}
	a {
		margin: 8px;
	}
	.exp {
		margin-top: 150px;
		margin-left: auto;
		margin-right: auto;
		width: 85%;
		height: auto;
	}
}