The black home page switching to the white (or cream) internal pages reflects the yin/yang aesthetic.
Black to white.
Darkness to light.
Ignorance to knowledge.
Yin is black, mysterious, hidden, secret, arcane, esoteric.
Yang is white, revealed, explained.
The new student - on approaching our class/website - is approaching the mystery from a position of ignorance and confusion.
Entering the site begins the journey to understanding.