.mobile_nav {
    position: absolute;
    display: block;
    top: 20px;
    right: 15px;
    transition: transform 0.5s cubic-bezier(0.694, 0.048, 0.335, 1), background 0.3s;
    transform: translateY(0);
    z-index: 10;
    font-family: 'Space Grotesk';
    filter: grayscale(60%);
}

/* show navbar when width above 768px */
@media (max-width: 768px) {
    .mobile_nav {
        display: block;
    }
}

.menu-down a {
    display: inline-block;
    width: 100%;
    color: #fff;
    font-size: 1.2em;
    padding: 0.6em;
}
.menu-down a:hover,.menu-down a:active,.menu-down a:focus {
    background-color: rgb(155, 81, 35);
}
.menu-down {
    list-style-type: none;
    position: absolute;
    border-radius: 4px;
    right: 0;
    top: 35px;
    min-width: 220px;
    margin-top: 5px;
    display: block;
    max-height: 0;
    padding: 0;
    overflow: hidden;
    transition: 0.3s ease-out;
}
.menu-down li {
    border: 1px solid gray !important;
    background-color: #5a5957 !important;
}
.menu-down.collapse-1 {
    max-height: 18em;
}
.nav-toggle {
    display: block;
    border-radius: 5px;
    background-color: #5a5957 !important;
    float: right;
    height: 38px;
    width: 38px;
    cursor: pointer;
    padding: 8px 8px;
}
.nav-toggle span {
    position: relative;
    display: block;
    height: 2px;
    width: 100%;
    margin-top: 4px;
    background-color: #fff;
    transition: .25s;
}
.nav-toggle.open span:first-child {
    transform: rotate(45deg) translate(4.4px, 4.4px);
}
.nav-toggle.open span:nth-child(2) {
    width: 0%;
    opacity: 0;
}
.nav-toggle.open span:last-child {
    transform: rotate(-45deg) translate(4.4px, -4.4px);
}