Vimeo Video Styling

style.css

.embed-container {
  --video--width: 1296; 
  --video--height: 540;

  position: relative;
  padding-bottom: calc(var(--video--height) / var(--video--width) * 100%); /* 41.66666667% */
  overflow: hidden;
  max-width: 100%;
  background: black;
}

.embed-container iframe,
.embed-container object,
.embed-container embed {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}