I want to highlite a relativ positioned div element from a layer below, by making everything around it darker.

What I have tried:

• Copy the position of the original element, and the element itself and then insert that element at the copied position
• Construct the darker layer out of 4 rectangles so that this creates a negative rectangle, where the heart element I want to highlight shines through (picture 2)

Has anyone a really smart idea of how to achieve this? Both solutions, kind of work, but are really prone to errors.