Variables in Less help you keep your files organized and easy to maintain. They allow you to specify widely-used values in a single place and then reuse them throughout your Less code. The properties of the final style sheet can be set with variables. So, imagine that you don't have to search for every declaration of a specific color or value in your style sheets any more. How does all of this work? Variables will start with @ and have a name. Examples of such variables include @color, @size, and @tree. To write the name, you are allowed to use any alphanumeric character, underscores, and dashes. This means that @this-is-variable-name-with-35-chars is a valid variable name.
Tip
Although alphanumeric characters, underscores, and dashes are used in variable names in this book, the specifications allow you to use any character, with a few exceptions. The specifications find their origin in the CSS grammar (which you can view at http://www.w3.org/TR/CSS21/grammar.html). Names starting...