Dear as you already mentioned about the best library name Quaid e Azam library. so I believe that's the best in lahore.
But in my opinion(maybe some members won't agree) the concept of library is no more valid as it was used to be once when people had no other channels to learn. Now a days you have wide access to digital media,virtual libraries,forums, academies,private coaching etc etc.
So in my humble opinion its not worth wasting time in libraries at least for css. You will find a lot of stuff outside library with little effort and time and that will be more organized and save a lot of your time which you can utilize in better preparation of css.
I believe joining library is just making yourself believe that you got serious about css and if I particulalr talk about Quaid e azam library though a very good one but mostly css aspirants join it to have a good time pass.
These are all my personal observations no offence to any person who favours Libraries. thank you.