Thanks tried the code

Change AnchorLink Text on ASP.Net Button Click using C# and VB.Net

No change the label lSchool still shows correctly as color=white but the menu is still black.

I set the textdesc = texte

lFound.Attributes.Add("Class", textdesc)
lSchool.Attributes.Add("Class", textdesc)
cbAll.Attributes.Add("Class", textdesc)
FontChange.Attributes.Add("class", textdesc)

.texte {
    color: White !important;
}
.textf {
    color: Black !important;
}
.textg {
    color: Blue !important;
}