* {
	margin: 0;
    	padding: 0;
}

body {
	font-family: Verdana, Arial, Helvetica, sans-serif;
    font-size: 87.5%;
	width: 706px;
	background-color: white;
	margin: 15px auto;
	padding: 20px;
}

h2 { 
	font-size: 125%;
	margin-bottom: .5em;
	clear: both;
}

nav {
	margin-bottom: 2em;
}
/* The styles for the operation of the 3-tier navigation menu */
#nav_menu ul {
	list-style: none;
	position: relative;    /* So the first submenu can be positioned within the main menu */
}
#nav_menu ul li {
	float: left;
}
#nav_menu ul ul {
	display: none;         /* Don't display submenu until hover of the li element */
	position: absolute;
	top: 100%;             /* Position the submenu at the bottom of the main menu */
}
#nav_menu ul ul li {
	float: none;           /* Display the submenus vertically */
	position: relative;    /* So the second submenu can be positioned within the first submenu */
}
#nav_menu ul ul li ul {
	position: absolute;
	left: 100%;            /* Position the second submenu at the right side of the li element */ 
	top: 0;                /* Position the second submenu at the top of the li element */
}
#nav_menu ul li.lastitem ul li ul {
	position: absolute;
	left: -100%;           /* Position the second submenu at the left side of the li element */ 
	top: 0;                /* Position the second submenu at the top of the li element */
}
#nav_menu ul li:hover > ul {
	display: block;        /* Display the submenu on hover of the li element */
}
#nav_menu > ul::after {
	content: "";
	display: block;
	clear: both;
}

/* The styles for the formatting of the 3-tier navigation menu */
#nav_menu ul {
	margin: 0;
	padding: 0;
}
#nav_menu ul li a {
	text-align: center;
	display: block;
	width: 176px;
	padding: 1em 0;
	text-decoration: none;
	background-color: blue;
	color: white;
	font-weight: bold;
}
#nav_menu ul li a.lastitem {
	width: 178px;               /* So the menu fills the 706px width of the page */
}
#nav_menu ul li a.current {
	color: yellow;
}
#nav_menu ul li a:hover, #nav_menu ul li a:focus {
	background-color: gray;
}