@media (min-width: 576px) { ... }

/*Medium devices (tablets, 768px and up)*/
@media (min-width: 768px) {
.navbar-nav {
    margin-left: 147px;
}
ul.navbar-nav li.dropdown:hover ul.dropdown-menu {
 display: block!important;
}
 }

/*Large devices (desktops, 992px and up)*/
@media (min-width: 992px) { 
.navbar-expand-lg .navbar-nav .dropdown-menu {
    position: absolute;
    top: initial;
}
 }

/*X-Large devices (large desktops, 1200px and up)*/
@media (min-width: 1200px) { ... }

/*XX-Large devices (larger desktops, 1400px and up)*/
@media (min-width: 1400px) { ... }

@media (max-width: 575.98px) { ... }

/*`md` applies to small devices (landscape phones, less than 768px)*/
@media (max-width: 767.98px) {

.carousel {
    padding-top: 68px;
} 
.heading{
    font-size: 1.5rem;
 }
 .navbar {
    background: #00ccb1;}
    
 .navbar-toggler-icon{background-image:url(../images/logo/bar.png) }
}

/*`lg` applies to medium devices (tablets, less than 992px)*/
@media (max-width: 991.98px) { ... }

/*`xl` applies to large devices (desktops, less than 1200px)*/
@media (max-width: 1199.98px) { 
.navbar-nav .nav-item .nav-link, .nav-link.active {
    font-size: 13px;
}
 }

/*`xxl` applies to x-large devices (large desktops, less than 1400px)*/
@media (max-width: 1399.98px) { 
    .nav-item {
    margin-right: 10px;
} 
}