@media screen and (min-width:769px){
    .navbar-brand{
        display: none;
    }
}
@media screen and (max-width:768px){
    .navbar {
        padding: 10px;
    }
    .navbar-brand{
        display: block;
    }    
    .header-top{
        display: block;
        text-align:center;
    }
    .header-top .search{
       margin-top: 20px;
    }
    .navbar-dark .navbar-nav a.nav-link {
        width: 100%;
        text-align: center;
        padding: 1rem 0;
        color: #fff;
        margin: 0 1px;
        font-size: 16px;
    }    
}