#main_menu {
    width: 100%;
    position: fixed;
    top: 0px;
    left: 0px;
    font-size: 1.5em;
    overflow: hidden;
    text-align: center;
    margin-top: -8px;
    background-color: rgba(20,20,20,0.9);
    z-index: 1000;
}

#main_menu:hover {
    background-color: rgb(20,20,20);
}

#main_menu ul {
    text-align: center;
}

#main_menu ul li {
    display: inline-block;
}

#main_menu ul li a {
    display: block;
    padding: .5em 1em;
    color: white;
    background-color: rgba(255,255,255,0);
    transition: background-color 0.2s ease-out, color 0.2s ease-out;
    -webkit-transition: background-color 0.2s ease-out, color 0.2s ease-out;
    -moz-transition: background-color 0.2s ease-out, color 0.2s ease-out;
}

#main_menu ul li a:hover,
#main_menu ul li a:focus,
#main_menu ul li a.selected {
    background-color: darkorange /*#992600/*rgba(255,255,255,0.5)*/;
    color: black;
    text-decoration: none;
}


/* MEDIA QUERIES */

@media only screen and (max-width: 900px) { /*max-device-width*/
    #main_menu {
        font-size: 1.2em;
    }
}