You may wonder how the library's windows were glowing as if lit from both the inside and outside. (Or maybe you don't care, but tough for you 'cos I'm gonna explain anyway!) Being as the city is built almost entirely within the mountain range, it gets very little natural light. Sun-wells in major common areas are used to direct as much of the days natural light into the city as they can, but they can only do so much - and an early experiment with a system of mirrors to redirect the light elsewhere ended poorly when one was knocked slightly off-balance and set fire to a decorative display it was meant to be gently illuminating. As such, many of the 'windows' in larger buildings - like the library - are in fact enchanted glass, magicked to give off a natural daylight glow more-or-less around the clock. The tone shifts between 'day' and 'moonlit night' accordingly for the time of day, but they ensure no corner of the city is ever shrouded in the kind of darkness one normally finds in deep caves.

-Reyn