#logo { width: 10%;
        float : left;
       }

#header {
    text-align: center;
    margin: auto;

}

 #nav {
 	margin: auto;
 	font-size : 1em;
 }



 #nav ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #333;
}

 #nav li {
    float: left;
} 	

 #nav li a {
    display: block;
    color: white;
    text-align: center;
    padding: 14px 64px;
    text-decoration: none;
}

 #nav a:hover:not(.active) {
    background-color: red;

}

 #nav .active {
    background-color:#4CAF50;
}


 #mainContent {
 	clear : both;
 	margin-top: 2em;
 }