Example

/*----------------------------------------------------------------
    768px Breakpoint
----------------------------------------------------------------*/

@media handheld, only screen and (max-width:48em) {

    header {
        position: relative !important;
        background-color: #fff !important;
    }

    #brand a,
    nav a {
        color: #333 !important;
    }

    nav a:hover {
        color: #fff !important;
    }

    nav,
    #menu-toggle {
        display: block;
    }

    #menu-toggle {
        float: right;
        clear: none;
    }

    nav {
        float: none;
        clear: both;
    }

    nav > ul {
        margin-top: 2em;
    }

    #brand{
        display:inline;
        float:left;
    }

    #brand h1 {
        line-height: 1.8;
        display:inline;
        float:left;
    }

    nav > ul {
        display: none;
    }

    nav > ul,
    nav > ul > li {
        float: none;
    }

    .sub-arrow {
        display: none;
    }

    nav > ul li > a {
        display: block;
        margin: 0;
        padding: 0.625rem 0;
        border-bottom: 1px solid #DDD !important;
        line-height: 1.250rem;
    }

    nav > ul > li > a:hover {
        -webkit-border-radius: 0 !important;
        -moz-border-radius: 0 !important;
        border-radius: 0 !important;
    }

    nav > ul li.last > a,
    nav > ul li.last > a:hover {
        border-bottom: none !important;
    }

    nav > ul > li.menu-item {
        padding: 0 !important;
    }

    nav ul.sub-menu > li > a {
        -webkit-border-radius: 0 !important;
        -moz-border-radius: 0 !important;
        border-radius: 0 !important;
    }

    nav ul.sub-menu > li > a {
        color: #666 !important;
        font-size: 0.688rem;
    }

    nav ul.sub-menu > li > a,
    nav ul li > a:hover {
        background-color: transparent !important;
    }

    nav ul li > a:hover {
        color: #FD685B !important;
    }

    nav > ul > li:hover > a {
        border-bottom: none;
    }

    nav ul.sub-menu {
        position: static;
        display: block;
        padding: 0 0 0 1.5em;
        width: inherit;
        -webkit-box-shadow: none;
        -moz-box-shadow: none;
        box-shadow: none;
    }