Explain findColorInvert

docs/documentation/overview/customize.html

@@ -50,14 +50,16 @@ npm install bulma
 // 2. Set your own initial variables
 // Update blue
 $blue: #72d0eb
-// Add pink
+// Add pink and its invert
 $pink: #ffb3b3
+$pink-invert: #fff
 // Add a serif family
 $family-serif: "Merriweather", "Georgia", serif
 
 // 3. Set the derived variables
 // Use the new pink as the primary color
 $primary: $pink
+$primary-invert: $pink-invert
 // Use the existing orange as the danger color
 $danger: $orange
 // Use the new serif family
@@ -79,7 +81,7 @@ $family-primary: $family-serif
           See the <strong>result</strong>: before and after
         </p>
         <p class="subtitle is-6">
-          Notice how the <code>$blue-invert</code> is now black instead of white, based on <code>findColorInvert(#72d0eb)</code></p>
+          As <code>$blue</code> has been updated, and since <code>$blue-invert</code> is automatically calculated with the <strong>function</strong> <code>$blue-invert: findColorInvert($blue)</code>, the <code>$blue-invert</code> is now black instead of white</p>
         </p>
         <figure>
           <img width="640" height="640" src="{{site.url}}/images/customize-before.png" alt="Customizing Bulma with Sass">