Hey folks,
With 5.0 here, my previous post for changing the nav bar colour is no longer working (see https://moodle.org/mod/forum/discuss.php?d=450595).
I no-longer work with Moodle, having changed jobs, but I am keeping my old site active for the time being and wanted to keep its code up-to-date (and with no one using it, I can break it for a few days and no one will care!)
The following code is ... kinda... tested in 5.0. Login, Language, Hamburger, title bar, sub menu and notifications all tested and working.
The main changes are the variable colour changes ( now --bs-* ) and some changes to the order and classes of elements.
Colours are achieved with the --bs-primary variable for the background colour, set in the Boost theme General page and then --bs-light and --bs-dark for the rest. Switch as necessary to fix contrast with your own branding.

/* top bar changes */
nav.navbar {
&.fixed-top {
background-color: var(--bs-primary) !important;
*:not( .dropdown-menu *, .popover-region-container * ) { color: var(--bs-light); }
.popover-region-container { color: var(--bs-dark); }
.nav-link {
&:hover,
&:active,
&:focus,
&.active { background-color: var(--bs-primary); border-bottom-color: var(--bs-light); border-bottom-width: 3px; }
}
/* with the bar using --primary, this makes the edit custom control switch invisible when turned on. following two target this switch */
.editmode-switch-form {
input:checked { background-color: var(--bs-danger); }
label:has(~ div > input:checked) { color: var(--bs-light) !important; }
}
/* Make sure the hamburger menus is the correct colour - change stroke values to match your scheme */
.navbar-toggler-icon { background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' width='30' height='30' viewBox='0 0 30 30'%3e%3cpath stroke='rgba%28255, 255, 255, 1%29' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e"); }
}
}





