Aspect ratio and font size

Fix font to div scale while keeping div in fixed aspect ratio.

HTML

<div>A B C D E F G</div>

CSS

*
{
    margin:0;padding:0;
}

div {
  width: 100vw; 
  height: calc(100vw * 9 / 16);

  font-size: 10vw;

  /* align center */
  margin: auto;
  position: absolute;
  top: 0px; right: 0px; bottom: 0px; left: 0px;

  /* visual indicators */
  background:
    url(data:image/gif;base64,R0lGODlhAgAUAIABAB1ziv///yH5BAEAAAEALAAAAAACABQAAAIHhI+pa+EPCwA7) repeat-y center top,
    url(data:image/gif;base64,R0lGODlhFAACAIABAIodZP///yH5BAEAAAEALAAAAAAUAAIAAAIIhI8Zu+nIVgEAOw==) repeat-x left center,
    silver;
}

/* 100 * 16/9 = 177.778 */
@media (min-width: 177.778vh) {
  div {
    height: 100vh;
    width: calc(100vh * 16 / 9);

    font-size: calc(10vh * 16 / 9);
  }
}