.container_slider {
  width:1200px;
  max-width:100%;
  margin:0 auto;
}

.slider {
  position:relative;
  height:0px;
  padding-bottom:42.833333333%; /*ce chiffre est egal a la largeur de l'image divisée par sa hauteur multiplié par cent */
  margin-top:24px;
  margin-bottom:24px;
}

.slider__after {
  position:absolute;
  top:0px;
  left:0px;
  z-index:1;
  width:100%;
  height:100%;
  background-size:cover;
  pointer-events: none;
}

.slider__before {
  position:absolute;
  top:0px;
  left:0px;
  z-index:2;
  width:50%;
  height:100%;
  background-size:cover;
  pointer-events: none;
  overflow:hidden;
}

.slider__before:before {
  content:'2016';/*affiché a gauche */
  position:absolute;
  left:8px;
  top:8px;
}

.slider__after:before {
  content:'2025'; /*affiché a droite */
  position:absolute;
  right:8px;
  top:8px;
}

.slider__separator {
  position:absolute;
  left:50%;
  width:2px;
  top:0px;
  bottom:0px;
  background:rgba(255,255,255,0.7);
  box-shadow: 0 5px 10px 0px rgba(0,0,0,0.5);
  cursor:ew-resize;
  z-index:3;
  transform:translateX(-50%);
}

.slider__range {
  position:absolute;
  width:100%;
  bottom:0px;
  z-index: 3;
  appearance: none;
  background:rgba(255,255,255,0.3);
  outline:none;
  margin:0px;
}

.slider__range::-webkit-slider-thumb {
  -webkit-appearance: none;
  width:12px;
  height:16px;
  background:white;
}

.slider__range::-moz-slider-thumb {
  -moz-appearance: none;
  width:12px;
  height:16px;
  background:white;
}

.slider--2016_25 .slider__before {
  background-image: url("../connaissances_faune_et_sujets_generaux/imgs/paysage-compare2016.jpg"); 

}

.slider--2016_25 .slider__after {
  background-image: url("../connaissances_faune_et_sujets_generaux/imgs/paysage-compare2025.jpg");
}

.slider--2016_25 .slider__separator:before {
  content:'';
  width:32px;
  height:32px;
  border-radius:50%;
  border:solid 2px white;
  position:absolute;
  top:50%;
  left:50%;
  transform:translate(-50%, -50%);
}

.slider--2016_25 .slider__range {
  display:none;
}

.slider--2016_25 .slider__before:before, 
.slider--2016_25 .slider__after:before {
  top:50%;
  transform:translateY(-50%);
  background:rgba(255,0,0,0.5);
  padding:8px 16px;
  border-radius:8px;
  margin-left:8px;
  margin-right:8px;
}