Ugh... did they really use Papyrus as their reception desk font? And Comic Sans on their library sign? THEY DESERVED TO FAIL!!
Those winders on the stairwell turn definitely don't meet code. I had an apartment with stairs like that. Suicide if you take the wrong step. Nowadays a minimum 6" tread depth is required on the narrow edge, at least as of the building codes when I last had to design a staircase.
I think you would know these things, having more library experience than many of us. I saw some very narrow steps recently, in 'The Gay Mans House'. That's for sometime next year 😃
I have also been a draftsman. Old houses had very different ideas of proper stair design, and while many a grand staircase in a nice old house is perfectly serviceable by modern standards of tread depth and step rise, the stairs meant for servants are downright deadly. Many a cheap small home is also dangerous.
The rise from one step to the next should not exceed 8"/20cm and tread depth should be about 11"/27cm off the top of my head. There are more specific rules of thumb based on trade experience for the old timers and strict building code standards today.
I have been in a couple recently with 'bad stairs'. Very shallow, and they are not always old properties.