/* style slider-opacity   */

/* slider track  */
#bkgdOpaq {
  width: 400px;
  height: 10px;
  appearance: none;
  background: linear-gradient(90deg, #707275, #eaebeb);
  border-radius: 5px;
  box-shadow: inset 0 0 4px rgba(0,0,0,0.4);
  outline: none;
}

/*  slider thumb ( knob )  */
#bkgdOpaq::-webkit-slider-thumb {
  appearance: none;
  width: 28px;
  height: 28px;
  background: radial-gradient(circle, #e1efff, #8dbbfd);
  border: 1px solid #4e7bb9;
  border-radius: 50%;
  box-shadow: 0 0 4px rgba(0,0,0,0.5);
  cursor: pointer;
}

/* FirFox  */
#bkgdOpaq::-moz-range-thumb {
  width: 28px;
  height: 28px;
  background: radial-gradient(circle, #e1efff, #8dbbfd);
  border: 1px solid #4e7bb9;
  border-radius: 50%;
  box-shadow: 0 0 4px rgba(0,0,0,0.5);
  cursor: pointer;
}