diff --git a/app/assets/stylesheets/common/foundation/variables.scss b/app/assets/stylesheets/common/foundation/variables.scss
index ae0b4e01b..3acece625 100644
--- a/app/assets/stylesheets/common/foundation/variables.scss
+++ b/app/assets/stylesheets/common/foundation/variables.scss
@@ -39,24 +39,32 @@ $base-font-family: Helvetica, Arial, sans-serif !default;
   @return ((red($color) * .299) + (green($color) * .587) + (blue($color) * .114));
 }
 
-// Replaces dark-light-diff($primary, $secondary, 50%, -50%)
 // Uses an approximation of sRGB blending, GAMMA=2 instead of GAMMA=2.2
-@function choose-grey($percent) {
+@function srgb-scale($foreground, $background, $percent) {
   $ratio: ($percent / 100%);
   $iratio: 1 - $ratio;
-  $pr2: red($primary) * red($primary);
-  $pg2: green($primary) * green($primary);
-  $pb2: blue($primary) * blue($primary);
-  $sr2: red($secondary) * red($secondary);
-  $sg2: green($secondary) * green($secondary);
-  $sb2: blue($secondary) * blue($secondary);
-  $rr2: $pr2 * $ratio + $sr2 * $iratio;
-  $rg2: $pg2 * $ratio + $sg2 * $iratio;
-  $rb2: $pb2 * $ratio + $sb2 * $iratio;
-  $rr: sqrt($rr2);
-  $rg: sqrt($rg2);
-  $rb: sqrt($rb2);
-  @return rgb($rr, $rg, $rb);
+  $f_r2: red($foreground) * red($foreground);
+  $f_g2: green($foreground) * green($foreground);
+  $f_b2: blue($foreground) * blue($foreground);
+  $b_r2: red($background) * red($background);
+  $b_g2: green($background) * green($background);
+  $b_b2: blue($background) * blue($background);
+  $r_r2: $f_r2 * $ratio + $b_r2 * $iratio;
+  $r_g2: $f_g2 * $ratio + $b_g2 * $iratio;
+  $r_b2: $f_b2 * $ratio + $b_b2 * $iratio;
+  $r_r: sqrt($r_r2);
+  $r_g: sqrt($r_g2);
+  $r_b: sqrt($r_b2);
+  @return rgb($r_r, $r_g, $r_b);
+}
+
+// Replaces dark-light-diff($primary, $secondary, 50%, -50%)
+@function choose-grey($percent) {
+  @return srgb-scale($primary, $secondary, $percent);
+}
+
+@function choose-gray($percent) {
+  @return choose-grey($percent);
 }
 
 @function dark-light-diff($adjusted-color, $comparison-color, $lightness, $darkness) {