I'm from Europe too. Blue(ish) is daylight colour while red(ish) is night colour. Staring at blue light hinders melatonine production, affecting the sleep cycle. Hence the existence of products like Redshift [0] and Twighlight [1]. Increasingly, this is built into visual interfaces, both my Gnome and Android have things called "night light" or something similar.
[0]: http://jonls.dk/redshift/
[1]: https://play.google.com/store/apps/details?id=com.urbandroid...