.presentation-background {
  height: 200vh;
  background-color: rgba(2, 8, 42, 0);
  background-attachment: scroll;
}

.presentation-image {
  background-attachment: fixed;
  background-repeat: no-repeat;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
  background-position: 50% 0%;
}

.presentation-content {
  position: relative; 
  height: 100%;
}
.presentation-item {
  height: 75vh;
}

.presentation-item > div {
  position: relative;
  top: 35%;
}

.presentation-item.main {
  position: inherit;
  opacity: 0;
  z-index: -100;
}

.presentation-item.main.active {
  position: inherit;
  opacity: 1;
  z-index: 1;
}

.presentation-item.secondary > div {
  padding: 60px 120px;
  background: rgba(0,0,0,0.3);
}

.presentation-item.secondary.active > div {
  left: 0%;
}

.presentation-item, .presentation-item > div {
  -webkit-transition: all 1s ease;
  -moz-transition: all 1s ease;
  -o-transition: all 1s ease;
  transition: all 1s ease;
}

.parallax-background {
  width: 100%;
  height: 50vh;
  background-attachment: fixed;
  background-repeat: no-repeat;
  -webkit-background-size: 100%;
  -moz-background-size: 100%;
  -o-background-size: 100%;
  background-size: 100%;
  background-position: center center;
}

.subfooter-background {
  width: 100%;
  height: 120vh;
  background-attachment: scroll;
  background-repeat: no-repeat;
  -webkit-background-size: auto 100%;
  -moz-background-size: auto 100%;
  -o-background-size: auto 100%;
  background-size: auto 100%;
  background-position: top center;
}

.black-background {
  background-color: #040404;
}

#cam-24 {
  border: 10px solid rgba(255,255,255,0.2);
}


@media (min-width: 300px) {
  .presentation-item.secondary > div {
    padding: 60px 40px;
  }

  .presentation-image {
    background-attachment: scroll;
    -webkit-background-size: auto 100%;
    -moz-background-size: auto 100%;
    -o-background-size: auto 100%;
    background-size: auto 100%;
  }

  .parallax-background {
    background-attachment: scroll;
    -webkit-background-size: auto 100%;
    -moz-background-size: auto 100%;
    -o-background-size: auto 100%;
    background-size: auto 100%;
  }

  .subfooter-background {
    -webkit-background-size: auto 100%;
    -moz-background-size: auto 100%;
    -o-background-size: auto 100%;
    background-size: auto 100%;
  }
}

@media (min-width: 576px) {
  .presentation-item.secondary > div {
    padding: 60px 40px;
  }

  .presentation-image {
    background-attachment: scroll;
    -webkit-background-size: auto 100%;
    -moz-background-size: auto 100%;
    -o-background-size: auto 100%;
    background-size: auto 100%;
  }
  
  .parallax-background {
    background-attachment: scroll;
    -webkit-background-size: auto 100%;
    -moz-background-size: auto 100%;
    -o-background-size: auto 100%;
    background-size: auto 100%;
  }

  .subfooter-background {
    -webkit-background-size: auto 100%;
    -moz-background-size: auto 100%;
    -o-background-size: auto 100%;
    background-size: auto 100%;
  }
}

@media (min-width: 768px) {
  .presentation-item.secondary > div {
    padding: 60px 40px;
  }

  .presentation-image {
    background-attachment: fixed;
    -webkit-background-size: auto 100%;
    -moz-background-size: auto 100%;
    -o-background-size: auto 100%;
    background-size: auto 100%;
  }

  .parallax-background {
    background-attachment: fixed;
    -webkit-background-size: 100%;
    -moz-background-size: 100%;
    -o-background-size: 100%;
    background-size: 100%;
  }

  .subfooter-background {
    -webkit-background-size: 100%;
    -moz-background-size: 100%;
    -o-background-size: 100%;
    background-size: 100%;
  }
}

@media (min-width: 992px) {
  .presentation-image {
    background-attachment: fixed;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
  }
}

@media (min-width: 300px) and (orientation:portrait) {
  .presentation-background {
    height: 150vh;
  }
  
  .presentation-image {
    background-attachment: scroll;
  }

  .presentation-content {
    height: 50%;
  }
  
  .presentation-item.secondary {
    visibility: hidden;
  }
}

@media (min-width: 760px) and (orientation:portrait) {
  .presentation-background {
    height: 400vh;
  }

  .presentation-image {
    background-attachment: fixed;
  }

  .presentation-content {
    height: 100%;
  }

  .presentation-item.secondary {
    visibility: visible;
  }
}