code: function ( hex, l ) {
  
          // validate hex string
          hex = String(hex).replace(/[^0-9a-f]/gi, '');
          if (hex.length < 6) {
              hex = hex[0]+hex[0]+hex[1]+hex[1]+hex[2]+hex[2];
          }
          l = l || 0;
  
          // convert to decimal and change luminosity
          var rgb = "#", c, i;
          for (i = 0; i < 3; i++) {
              c = parseInt(hex.substr(i*2,2), 16);
              c = Math.round(Math.min(Math.max(0, c + (c * l)), 255)).toString(16);
              rgb += ("00"+c).substr(c.length);
          }
  
          return rgb;
  
      }
docs: ---------------------- Color function ----------------------