use hex instead of hsl

Author: geoffrey-wu

client/bootstrap/dark.css

@@ -1,6 +1,6 @@
 // Variables taken from https://github.com/ForEvolve/bootstrap-dark/blob/master/scss/_dark-variables.scss
 
-$body-bg:     hsl(210, 14%, 15%);
+$body-bg:     #21262c;
 $body-color:  #d3d3d3;
 
 $custom: #dfebfb;