In LESS, the nested rules is a group of CSS properties which enables using properties of one class into another class and includes class name as its properties.
In this lesson we will learn to create mixins for converting PX to EM or EM to PX. The mixin will return the value and it can be used in any property values.
Using LESS you can create Mixins which are very similar to functions. Mixins are actually used for assigning multiple properties to a CSS selector.
CSS is just some lines of static code. There is nothing dynamic in CSS. To extend the productivity many CSS developers have developed many extensions for it. CSS preprocessors are a part of it. And LESS is one of them.