Sass offers a long list of built-in functions. They serve all kinds of purposes including string manipulation, color related operations, and some handy math methods such as random() and round().

To exhibit one of the more simple Sass functions, we will create a quick snippet that utilizes darken($color, $amount) to make an on-hover effect.

$awesome-blue: #2196F3;

a {
  padding: 10px 15px;
  background-color: $awesome-blue;

a:hover {
  background-color: darken($awesome-blue,10%);