Devtools Image

Problem
I tried changing the color of the background when adding the class checked to the object, but it won't change the color and just appears crossed out in devTools.
Code:
.doctheme .check { 
  position : relative;
  top      : -2.5px;
  width    : 30px;
  height   : 30px;
  left     : 45px;
  border-radius       : 50%;
  background-color    : #136;
  transition-duration : .4s;
  }
.checked {
  translate        : -42.5px;
  background-color : #FDA;
  }
 
    