iframe,video {
  width: 90vw;
  height: calc(90vw / 16 * 9);
}

@media only screen and (min-width: 600px) {
  main {
    font-size: 20px;
  }
}

@media only screen and (min-width: 1000px) {
  main {
    font-size: 24px;
  }
}

@media only screen and (min-width: 1025px) {
  iframe,video {
    width: 40vw;
    height: calc(40vw / 16 * 9);
    margin: 1vw;
  }
  #video {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
  }
  #video::after {
    content: "";
    flex: auto;
  }
}
@media only screen and (min-width: 2000px) {
  main {
    font-size: 32px;
  }
}