:root {

}

@media (min-width: 768px) {
    ...
}

.toast {
    --bs-toast-font-size: 1rem;
    width: 600px;
}

.toast.bg-success .toast-header, .toast.bg-danger .toast-header, .toast.bg-secondary .toast-header {
    color: white !important;
}

.toast.bg-success .btn-close, .toast.bg-danger .btn-close, .toast.bg-secondary .btn-close {
    filter: invert(1) grayscale(100%) brightness(200%);
}

.toast-container {
    position: absolute;
    left: 50% !important;
    transform: translateX(-50%) !important;
    padding-top: 5rem;
}