Why doesn't an element appear on hover in Firefox?

Question

css

Hello.
Tell
me, why does not an element appear in firefox on hover?
In chrome, everything is fine, here is a piece of code:

<div class="block">
        <img src=""">
        <div class="hover">Hover</div>
    </div>

.block{	
        width: 25%;
        margin: 0 -4px -4px 0;
  display: inline-block;
  position: relative;
  overflow: hidden;
  cursor: pointer;}

.block:after{
  content: "";
  width: 100%;
  height: 100%;
  display: block;
  position: absolute;
  top: 0;
  left: 0;	
  transition: 0.5s;
}

.block:hover:after{
  background-color: rgba(240,146,41,0.7);
  transition: 0.5s;
  
}



.hover{
  width: 100%;
  display: inline-block;
  position: absolute;
  top: 43%;
  color: #fff;
  z-index: 100;
  opacity: 0;
  transition: 0.5s;
}

.block:hover .hover{
  opacity: 1;
  transition: 0.5s;
}

Answer 1

Works
Before block in css forgot the dot for the class!