html, body {
    font-family: Arial, Helvetica, sans-serif;
}

/* define a fixed width for the entire menu */
.navigation {
    width: 100%;
}

/* reset our lists to remove bullet points and padding */
.mainmenu {
    list-style: none;
    padding: 0px;
    margin: 0px;
    border-bottom: 1px solid #fff;
}

.submenu {
    list-style: none;
    padding: 0px;
    margin: 0px;
}

/* make ALL links (main and submenu) have padding and background color */
.mainmenu a {
    display: block;
    background-color: #111;
    text-decoration: none;
    padding-left: 5px;
    color: #fff;
    border-top: 1px solid #fff;
    border-left: 1px solid #fff;
    border-right: 1px solid #fff;
    margin: 0px;
}

    /* add hover behaviour */
    .mainmenu a:hover {
        background-color: #ffcd00;
            color: #111;

    }


/* when hovering over a .mainmenu item,
  display the submenu inside it.
  we're changing the submenu's max-height from 0 to 200px;
*/

.mainmenu li:hover .submenu {
    display: block;
    max-height: 200px;
}

/*
  we now overwrite the background-color for .submenu links only.
  CSS reads down the page, so code at the bottom will overwrite the code at the top.
*/

.submenu a {
    background-color: #999;
}

    /* hover behaviour for links inside .submenu */
    .submenu a:hover {
        background-color: #666;
    }

/* this is the initial state of all submenus.
  we set it to max-height: 0, and hide the overflowed content.
*/
.submenu {
    overflow: hidden;
    max-height: 0;
    -webkit-transition: all 0.5s ease-out;
}