“If the designer hasn`t explained the direction of the shadow, its blur and transparency, in the specifications the developer does the shadow himself “by eye”. With all the consequences coming…” I don´t know what to say. Maybe, ten years ago… but today using Sketch, Adobe XD or Figma (Even photoshop) you can define shadows using the same parameters that devs will use in the front end and copy the css style of any UI element. Currently we use handoff software such as Zeplin or Avocode or Invision Inspect to make easier the work of the developers. Of course, you can use Axure to make your design but I think that today we have a great collection of new software very well designed and focused in the needs of the UI designers.