#logo {
    margin: auto;
    width: 50%;
    padding: 10px;

}

.mainContent {
    width: 75%;
    margin: auto;
    padding: 10px;

}

.center {
    margin: auto;
    width: 50%;
    padding: 10px;
}

ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
}

li {
    float: left;
}

li a {
    display: block;
    color:#333;
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
}

/* Change the link color to #111 (black) on hover */
li a:hover {
    color: red;
}

.active {
    color:red;
}