.toast-message {
    color: white !important;
    /* O cualquier otro color que desees. */
}

.toast-success {
    background-color: green !important;
}

.toast-error {
    background-color: #e31919 !important;
}

.toast-warning {
    background-color: #d9aa11 !important;
}

.toast-info {
    background-color: #4d99d6 !important;
}