Google's Material Design blue
Blue was used as primary- and backgroundcolor because it fits the most criteria from Kolenda's table. Arsnova.click has to exude competence and users should like the website and get the feeling of gaining knowledge.
The accent colors, red and orange with red being the main accent color, all serve the same purpose. They are used to exude excitement and attention in order to wake up the students from their "listening sleep" and stimulate them to participate. Green is used to signal switches that are "on".
