Fix SCSS variables

[pstavirs]

I'm not a web developer, so I may be mistaken, but I think spin is a LESS construct not SASS. The corresponding SASS function is adjust-hue

diff --git a/_sass/_variables.scss b/_sass/_variables.scss
index a63f9da..b587d9d 100644
--- a/_sass/_variables.scss
+++ b/_sass/_variables.scss
@@ -22,7 +22,7 @@ body {
 $body-color         : #fff;
 $text-color         : #222;
 $base-color         : #343434;    
-$comp-color         : spin($base-color, 180); 
+$comp-color         : adjust-hue($base-color, 180);
 $border-color       : #ddd;
 $white              : #fff;
 $black              : #000;

[mmistakes]

Originally the stylesheets were built with Less and then I converted them to SCSS. I probably just missed this.