Ouch!

Tip rápido, escribir variables de una manera modular.

$color-border;
$color-border-dark;
$color-border-light;
$color-highlight;
$color-link;
$color-link-dark;
$color-link-light;
$color-text;
$color-text-light;
$color-text-lightest;

Una lectura un poco más larga sobre el tema, Thoughts For Better Variable Organization In SASS.