The following rules must be followed:

- The CSS must be valid conform CSS 2.1 specification. This can be tested using the W3C validator

The following recommendations could be followed:

* Proprieties:

~** alphabetical order;

~** 2 spaces indentation;

~** use of CSS shorthands;

* Grouping:
~** comment headers for separation and grouping of different parts of the code;

* Localization:
~** "Overwrites" and "Should be in"  comments for dependencies overwriting;