.contenedor__item {
  max-width: 1000px;
  margin: auto;
} 

.contenedor__item img {
  width: 100%;
  /*height: 700px;*/
  object-fit: cover;
  margin-top: 35px;
}

.contenedor__item img:nth-child(1) {
  /*margin-top: 0;*/
}

/*Botón de ir arriba------------------------*/
.back-to-top {
  position: fixed;
  right: 5%;
  bottom: 2rem;
  display: block;
  background: #000;
  text-align: center;
  transition: all 0.5s linear;
  cursor: pointer;
  opacity: 0.3;
  z-index: 100;
}
.back-to-top img{
  width: 50px;
}
.back-to-top:hover {
  opacity: 1;
}

/*MEDIA QUERIES---------------------------------------------------------------------------------------------------*/

@media (max-width: 1024px) {
.contenedor__item img {
  /*height: 550px;*/
}
}

@media (max-width: 819px) {
#contenedor::before {
  height: 75px;
}
}

@media (max-width: 720px) {
.contenedor__item img {
  /*height: 450px;*/
}
}

@media (max-width: 570px) {
.contenedor__item img {
  /*height: 300px;*/
  margin-top: 20px;
}
}