Chapter 5. Extending and Referencing
In this chapter, we will cover the following topics:
- Referencing parent selectors with the 
&operator - Referencing to the parent selector more than once
 - Changing the selecting order with the 
&operator - Using 
extendto merge selectors - Using 
extendinside a ruleset - Extending with the 
allkeyword - Extending with media queries
 - Using 
extendto reduce the compiled CSS size - Using 
extendas an alternative for a mixin