body{
	font-family: sans-serif;
	margin: 0;
}

a{
	color: blue;
	text-decoration: none;
}
a:hover{
	text-decoration: underline;
}

header{
	text-align: center;
}

#header-nav ul{
	list-style-type: none;
}
#header-nav ul li{
	display: inline;
}
#header-nav ul li:after{
	content: " | ";
}
#header-nav ul li:last-child:after{
	content: "";
}

#container{
	display: flex;
}
#container nav{
	width: 25%;
	background-color: lightgrey;
}
#container article{
	width: 75%;
	margin-left: 1em;
	margin-right: 1em;
}

pre{
	background-color: whitesmoke;
	font-size: 1.2em;
}
code{
	background-color: whitesmoke;
	border-radius: 5px;
	padding: 3px;
}

.example{
	border-left: 0.2em solid lightblue;
	padding-left: 1em;
}

hr{
	margin: 1em;
	border: 1px solid black;
}