#slider {
  position: relative;
  width: 50%;
  margin: auto;
  display: flex;
  align-items: center;
}

#sliderPrecedent,
#sliderSuivant {
  cursor: pointer;
  transition: opacity 0.3s ease;
  opacity: 0;
  position: absolute;
  font-size: 100px;
  color: rgba(220, 220, 220, 0.8);
  background-color: rgba(0, 0, 0, 0.8);
  padding: 10px;
}

#sliderPrecedent {
  left: 0;
}

#sliderSuivant {
  right: 0;
}

#sliderSuivant, #sliderPrecedent{
    border: 0px; 
    background-color: rgba(0, 0, 0, 0); 
}


#slider:hover #sliderPrecedent,
#slider:hover #sliderSuivant {
  opacity: 1;
}

#slider img{
  width: 100%;
  height: 100%;
}