great article

The Open-Closed Principle

That's a great article by Robert C. Martin. It's one of those articles that really may change something in your programming. The principle is called Open-Closed and it says:SOFTWARE ENTITIES (CLASSES, MODULES, FUNCTIONS, ETC.) SHOULD BE OPEN FOR EXTENSION, BUT CLOSED FOR MODIFICATION.More about that here.

What exactly "Retina display" means in the context of the front-end development

If you are wonder what exactly "Retina display" means I'll suggest to check this great article in SmashingMagazine. I searched a lot for a simple explanation and that's the best one.