Tick down the darkness of `$grey-5` to meet WCAG contrast ratio req’ts

src/styles/variables.scss

@@ -20,7 +20,7 @@ $grey-4: #a6a6a6;
 // minus blue tint.
 $grey-semi: #9c9c9c;
 
-$grey-5: #7a7a7a;
+$grey-5: #767676;
 
 // Interim color variable for migration purposes, as the step between `$grey-5`
 // and `$grey-6` is large. Represents `base-mid` in proposed future palette,