.menu_bar {
    display:none;
}
header {
    width: 100%;
}
header nav {
    background: #673AB7;
    z-index: 1000;
    max-width: 1000px;
    width: 100%;
    margin: 10px auto;
}
header nav ul {
    list-style: none;
}
header nav ul li {
    display: inline-block;
    position: relative;
    font-size: 20px;
}
header nav ul li:hover {
    background: #D1C4E9;
}
header nav ul li a {
    color: #fff;
    display: block;
    text-decoration: none;
    padding: 20px;
}
header nav ul li a span {
    margin-right: 10px;
    font-size: 24px;
}
header nav ul li:hover .children {
    display: block;
}
header nav ul li .children {
    display: none;
    background: #512DA8;
    position: absolute;
    width: 150%;
    z-index:1000;
}
header nav ul li .children li {
    display: block;
    overflow: hidden;
    border-bottom: 1px solid rgba(255,255,255,.5);
}
header nav ul li .children li a {
    display: block;
}
header nav ul li .children li a span {
    float: right;
    position: relative;
    top: 3px;
    margin-right: 0;
    margin-left: 10px;
}
header nav ul li .caret {
    position: relative;
    top: 3px;
    margin-left: 10px;
    margin-right: 0px;
    font-size: 20px;
}

@media screen and (max-width: 800px) {
    body {
        padding-top: 80px;
    }
    .menu_bar {
        display: block;
        width: 100%;
        position: fixed;
        top:0;
        background: #673AB7;
        overflow-y: auto;
        -webkit-overflow-scrolling:touch;

    }
    .menu_bar .bt-menu {
        display: block;
        padding: 20px;
        color: #fff;
        overflow: hidden;
        font-size: 20px;
        font-weight: bold;
        text-decoration: none;
    }
    .menu_bar span {
        float: right;
        font-size: 40px;
    }
    header nav {
        width: 80%;
        height: calc(100% - 100px);
        position: fixed;
        right: 100%;
        margin: 0;
        overflow-y: auto;
        -webkit-overflow-scrolling:touch;
    }
    header nav ul li {
        display: block;
        border-bottom: 1px solid rgba(255,255,255,.5);
    }
    header nav ul li a {
        display: block;
    }
    header nav ul li:hover .children {
        display: none;
    }
    header nav ul li .children {
        width: 100%;
        position: relative;
    }
    header nav ul li .children li a {
        margin-left:20px;
    }
    header nav ul li .caret {
        float: right;
    }
}