port-ui/app/static/css/navigation.css

/* Top-level dropdown menu */
.nav-item .dropdown-menu {
    position: absolute; /* Important for positioning */
    top: 100%; /* Default opening direction: downwards */
    left: 0;
    z-index: 1050; /* Ensures the menu appears above other elements */
}

/* Submenu position */
.dropdown-submenu > .dropdown-menu {
    position: absolute;
    top: 0;
    left: 100%; /* Opens to the right */
    z-index: 1050;
}

/* Ensure a smooth transition */
.dropdown-menu {
    transition: all 0.3s ease-in-out;
}

nav.navbar.menu-header {
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
}
  
nav.navbar.menu-footer {
    border-top-left-radius: 0;
    border-top-right-radius: 0;
}