In real life, does a web developer remember all those selectors?

Very good question Amir. I don't think you do, however the more you work at it, the more all of this stuff starts to stick in your mind. What I've found is that over time, I've developed a trusted base set of stuff that I call upon in every project and the majority of that I can just roll out without consulting elsewhere.

Then there's a whole load of classes and selectors that one rarely uses unless a specific scenario crops up. But one will think, 'ah – that needs this sort of treatment' – where I know broadly how to achieve it, but have to refer elsewhere to get the code and notation pinned down.

Ultimately, as you practice your chosen code (be it CSS or some other language), bits and pieces will slowly seep into your blood and subconscious.

Don't worry – we all go through this. As long as you have passion for what you are doing, you'll naturally develop a thirst and curiosity for the nuances of the code and through that, you'll begin to intuitively know what's required on any given issue. The web community is out there to help you achieve those goals while you're growing your skills.

Good luck and keep coding! :-)