The color(s) green, blue, a mixture of green and blue, and white is/are claimed as a feature of the mark.
The mark consists of the stylized word "PHD" in white letters, surrounded by a quadrilateral-shaped background, in which the letter "P" has the background portion in green color, the letter "D" has the background portion in blue color, and the letter "H' has the background portion in a color that is a mixture of green and blue.