Often, we may find ourselves wanting to style things differently depending on their context.
Take emphasis as an example. In typical copy, presented in a roman (non-italic) type, we may wish to add emphasis to a word or phrase by using italics.
But what if we want to quote a block of text which also emphasizes something?
This is a quote from some famous person who undoubtedly has something very important to say.
If we want our block quote to be set in italics by default, then the visual style for emphasis needs to be different, but only when inside a blockquote.
This is where nested selectors come in handy.