body{
	font: 24px helvetica;
	background: linen;
}

.father{
	min-height: 400px;
	margin: 0px;
	padding: 0px;
	display: flex;
	flex-flow: row;
}
.father > article{
	margin: 3px;
	padding: 2px;
	border-radius: 9pt;
	background: lightskyblue;
	flex: 4;
	order: 2;
}
.father > nav{
	margin: 2px;
	padding: 3px;
	border-radius: 9pt;
	background:lightgreen;
	flex: 1;
	order: 1;
	text-align: center;
	align-items: center;
}

/*nav{*/
/*	text-align: center;*/
/*	align-items: center;*/
/*}*/
/*.p11{*/
/*	text-align: center;*/
/*	align-items: center;*/
/*	margin: 0 auto;*/
/*}*/
.father > aside{
	margin: 2px;
	padding: 3px;
	border-radius: 9pt;
	background: lightgreen;
	flex: 1;
	order: 3;
}
header,footer{
	display: block;
	margin: 4px;
	padding: 5px;
	border-radius: 9pt;
	min-height: 80px;
	border: 3px solid lightsalmon;
	text-align: center;
}


 /* CSS 样式可以在这里添加 */
body {
	font-family: Arial, sans-serif;
}
h1 {
	text-align: center;
}
ul {
	list-style-type: none;
	padding: 0;
	margin: 0 auto;
	width: 300px;
	text-align: center;
}
li {
	margin-bottom: 5px;
}
.a2 {
	display: block;
	margin: 5px;
	padding: 2px;
	background-color: #4CAF50;
	color: white;
	text-decoration: none;
	border-radius: 5px;
}
.a2:hover {
	background-color: #45a049;
}

.a3 {
	display: block;
	margin: 5px;
	padding: 2px;
	background-color: #008790;
	color: white;
	text-decoration: none;
	border-radius: 5px;
}
.a3:hover {
	background-color: #007882;
}
.a1 {
	display: block;
	margin: 3px;
	padding: 6px;
	background-color: #4CAF50;
	color: white;
	text-decoration: none;
	border-radius: 5px;
}
.a1:hover {
	background-color: #45a049;
}
@media all and (max-width: 640px) {
	.father {
		flex-flow: column;
	}
	.father > article,.father > nav,.father > aside{
		order: 0;
	}
	.father > nav > a{
	    margin: 5px 33px;
	}
	.father > aside,header,footer{
		min-height: 50px;
		max-height: 50px;
	}
	header h1{
		font-size: 18px;
	}
	footer p{
		font-size: 17px;
	}

}