body {
  background: url(../assets/img/empty-cinema.jpg),
  #000;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  font-family: sans-serif;
}
.wrapper {
  width: 90%;
  margin: auto;
  background: hsla(0, 0%, 0%, 0.2);
  padding-top: 73px;
}

h1, h2 {
  text-align: center;
  color: orange;
}

.box {
  position: relative;
  width: 80%;
  margin: auto;
}
:root {
  --size: 150px;
}
.play {
  display: block;
  width: var(--size);
  height: var(--size);
  position: absolute;
  top: 50%;
  left:50%;
  transform: translate(-50%, -50%);
  /* margin-left:calc( var(--size) * -1 / 2);
  margin-top: calc( var(--size) * -1 / 2); */
  filter: opacity(0.5);
}

.play:hover {
  filter: opacity(1);
  cursor: pointer;
}

video {
  max-width: 100%;
  height: auto;
}

.back,
.next {
    position: fixed;
    display: block;
    bottom: 50px;
    width: 100px;
    height: 100px;
    line-height: 100px;
    text-align: center;
    text-decoration: none;
    border-radius: 50%;
    background: navy;
    color: gold;
    cursor: pointer;
    box-shadow: 0 0 5px 2px hsla(0, 100%, 100%, 0.2);
  }
  .next {
    right: 50px;
  }
  .back {
    left: 50px;
  }
  .back:hover,
  .next:hover  {
    box-shadow: 0 0 5px 4px hsla(0, 100%, 100%, 0.5);
  }