MediaWiki:Vector.css

/* CSS placed here will affect users of the Vector skin */
/* Bring the text to 14px */
#mw-content-text {
  font-size: 0.900em;
}

#bodyContent {
  font-size: 0.900em;
}

#pmvideocontainer {height: 100%; width:100%; font-size: 0;}
#pmvideoleft, #pmvideoright {display: inline-block; *display: inline; zoom: 1; vertical-align: top; font-size: 12px; }
#pmvideoleft {margin:10px;}
#pmvideoright {margin:10px;}

.iframe-container {
  position: relative;
  overflow: hidden;
  width: 100%;
  padding-top: 56.25%; /* 16:9 Aspect Ratio (divide 9 by 16 = 0.5625) */
}

/* Then style the iframe to fit in the container div with full height and width */
.responsive-iframe {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  width: 100%;
  height: 100%;
}