@media (max-width: 991px) {
    .headermenu-holder{
        display:none;
        position: fixed;
        top: 5px;
        left: -200px;
        background: #C5C7C4;
        height: 100vh;
        width: 200px;
    }

    .headermenu{
        display:flex;
        flex-direction: column;
    }

    .headermenu li{
        margin:0;
        padding: 10px;
        border-bottom: 1px solid #bebebe;
    }
}