|<- [[Working with math operations]]|[[Creating list elements]] ->|

  * assombrir (darken)
  * éclairer (lighten)
  * complémentaire (complementary)
  * et bien d'autres -> http://sass-lang.com/documentation/Sass/Script/Functions.html

<code>
tr {
  background-color: $blue;
  &:hover {
    background-color: complement($blue);
  }
</code>