I believe the issue is that Fandom uses different encoding of username spaces on message walls. It's a pretty common issue. The current code is
a[href$=":Agent_Ladyfox0004"],
a[href$="/Agent_Ladyfox0004"] {
color: blueviolet;
}
And to fix it, it should be
a[href$=":Agent_Ladyfox0004"],
a[href$=":Agent%20Ladyfox0004"],
a[href$="/Agent_Ladyfox0004"] {
color: blueviolet;
}