Use the same colors but apply 12.5% opacity.
Solution boxes use 30% opacity
font-size: 18px;
}
+.challenge { background-color: #eec27520; }
+.callout { background-color: #f4fd9c20; }
+.challenge { background-color: #eec27520; }
+.checklist { background-color: #dfd2a020; }
+.discussion { background-color: #eec27520; }
+.keypoints { background-color: #7ae78e20; }
+.objectives { background-color: #daee8420; }
+.prereq { background-color: #9cd6dc20; }
+.solution { background-color: #ded4b94d; }
+.testimonial { background-color: #fc8dc120; }
+
blockquote p {
margin: 5px;
}