lighten(#d21a1a, 10%);
darken(#d21a1a, 10%);
Example usage:
#div1 {background: lighten(#d21a1a, 10%);}
#div2 {background: d21a1a;}
#div3 {background: darken(#d21a1a, 10%);}
This would output colors as displayed here:
See the Pen SCSS lighten & darken example by Martin Whitaker (@sirnightowl) on CodePen.13366