refactor(app-cta): move color to variable

Author: luiskcs89

src/components/app-cta/app-cta.scss

@@ -1,6 +1,6 @@
 .cta {
   height: 344px;
-  background: #008092;
+  background: $blue-green;
 
   @include media-breakpoint-down(sm) {
     height: 780px;

src/styles/_variables.scss

@@ -13,6 +13,7 @@ $gray-brown: #5d534e !default;
 $gray-dark: #292a2d !default;
 $black: #171719 !default;
 $blue: #638593 !default;
+$blue-green: #008092 !default;
 $indigo: #323c47 !default;
 $red: #dc3545 !default; // TODO
 $orange: #e88212 !default;