*{
  margin: 0;
  padding: 0;
}
html, body{
  background-color: #000;
  color: #fff;
  height: 100%;
  font-family: sans-serif;
}

body{
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}
.center{
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}
.part{
  height: 50%;
  width: 100%;
}
iframe{
  border: none;
}