I have finished the design of the lid for the case for the mini-power bank which can be used in small projects, where regulated voltage is not required.

I have also tested out a concept of having the indication with LEDs through a thinned plastic. A near cut-out has 0.2mm thickness, while the rest of the lid has thickness of 2 mm. When there is no light source inside of the enclosure, the near cut-out is not visible from outside.