Nowadays, nobody code raw CSS3 in real-world HTML5 Applications Development. Huge amount of monotonic repeated code is too hard to create and support. Usually, one of CSS preprocessors are used to implement CSS3 styles in more elegant way. LESS [http://lesscss.org/] is one of such approaches. It doesn’t need to spend a lot of time to start using it. Try online tool [http://lesscss.org/less-preview] to process LESS into CSS code.
First of all, LESS is pre-processor of special syntax into CSS code. Besides, CSS code is a correct LESS code as well. You can start porting your existing pure CCS3 project into LESS just by a copy-paste action. When we mark some section or module with specified CSS class we are going to format and style not just wrapper but all its inside components as well. LESS helps us in this most used case by its nested syntax. E.g., LESS code: