Issue 406 of A List Apart introduced what is now called the “lobotomized owl selector” — a powerful but simple CSS construct for reducing code bloat, speeding up development and simplifying the styling of dynamic Web content.
What does it look like, you ask? Just this: * + *
Built on the principle of exception-driven design, you can use this selector to specify universal rules regarding flow and layout, and then write exceptions as required. This becomes tremendously useful for grid-based designs.
Even the most complex systems must depend on foundational rules, and CSS is no different. Although modularisation of a complex interface is a necessary step in its maturation, any interface that does not follow basic governing tenets is going to lack clarity.
Highly recommended, even if you consider yourself an experienced frontend developer.