body {
  padding: 0;
  margin: 0;
  line-height: 0;
}

video {
  width: 100%;
  height: 100vh;
  position: relative;
}

.glavno {
  position: relative;
}

#predvajaj {
  display: none;
  font-size: 10rem;
  font-weight: bold;
  opacity: .7;

  position: absolute;
  left: 25%;
  top: 25%;
  width: 50%;
  height: 50%;
  border-radius: 100%;
  cursor: pointer;

  border-style: groove;
  border-width: 2rem;
  border-color: red;
  background-color: white;
}

.gumbi {
  position: fixed;
  bottom: 0;
  width: 100%;
  display: none;
}

.gumbi button {
  position: absolute;
  display: flex;
  width: 16rem;
  height: 16rem;
  border-radius: 100%;

  font-size: 10rem;
  font-weight: bold;
  justify-content: center;
  align-items: center;
  background-color: rgba(255, 255, 255, 0.5);
  border: none;
  cursor: pointer;
}

#levo {
  left: -3rem;
  bottom: -3rem;
}

#desno {
  right: -3rem;
  bottom: -3rem;
}

#ravno {
  left: calc(50% - 7.5rem);
  bottom: -3rem;
}

.predvajam .gumbi {
  display: block;
}