I do not understand the Reusable CSS with mixins lesson

HTML-CSS
4

Alright, let’s look at the directions:
image

  • It asks you to create a @mixin for border-radius and give it a $radius parameter
    Mixin is like a function, but it works differently.
  • It says it should use all the vendor prefixes, this means the browser that’s going to be used and the prefixes, so it’s
    -webkit-css-attribute, -moz-css-attribute, -ms-css-attribute. So with border-radius its going to be -webkit-border-radius and so on…