.background-cover, .slide {
  background-position: center center;
  background-repeat: no-repeat;
  background-size: cover;
  background-image: url(images/hero-bg.jpg);
}

.slide {
  height: 100vh;
}
.slide--1 {
  background-image: url(images/hero-bg2.jpg);
}
.slide--2 {
  background-image: url(images/hero-bg.jpg);
}
.slide--3 {
  background-image: url(images/hero-bg2.jpg);
}