.contenedor-slider {
  margin: auto;
  width: 85%;
  max-width: 900px;
  position: relative;
}

.slider {
  display: flex;
  width: 400%;
}

.slider__section {
  width: 100%;
}

.slider__img {
  display: block;
  width: 100%;
  height: 100%;
}

.btn-prev, .btn-next {
  width: 3.5rem;
  height: 100%;
  background: rgba(255, 255, 255, 0.0);
  color: #000;
  position: absolute;
  top: 0;
  font-size: 30px;
  font-weight: bold;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s;
  z-index: 6;
}

.btn-prev span, .btn-next span{
  display: block;
  margin: auto;
  position: absolute;
  top: 45%;
  left: 40%;
}

.btn-prev:hover, .btn-next:hover {
  background: rgba(255,255,255,0.8);
}

.btn-prev {
  left: -3.5rem;
}

.btn-next {
  right: -3.5rem;
}
#sombraIzq, #sombraDer{
  position: absolute;
  height: 100%;
  width: 600px;
  top: 0;
  z-index: 5;
}
#sombraIzq{
  background-image: linear-gradient(to left, rgba(255,255,255,0.6), rgba(255,255,255,0.2));
  right: 100%;
}
#sombraDer{
  background-image: linear-gradient(to right, rgba(255,255,255,0.6), rgba(255,255,255,0.2));
  left: 100%;
}
#textoSlide{
  position: absolute;
  bottom: 0;
  left: 0;
  height: 5rem;
  width: 100%;
  background-color: rgba(255, 255, 255, 0.6);
  font-size: 2.5rem;
  font-weight: 200;
  text-align: center;
}

@media only screen and (max-width: 850px) {
  .contenedor-slider{
    width: 100%;
  }
  .btn-prev {
    left: 0;
  }

  .btn-next {
    right: 0;
  }
  #textoSlide{
    height: 4rem;
    font-size: 2rem;
    z-index: 7;
  }
}