HA Floorplan - The room doesnt get brighter when lights switch on


I am following the floorplan example here - Floorplanner Home Example - Floorplan for Home Assistant and i am having some issues.

I have imported the svg, css and created the yaml as per the example (referring to my entities) and it works fine. However, when i use that over my own svg, when clicking on the room, the light switches on, but the room in the floorplan doesnt get brighter as in the example.

I have almost no idea about svg, but looking at the svg in the example, i have seen there is a layer on top of each room which makes it brighter or darker.

Is there any guide or something similar about how to do this? I just have the svg for my floorplan