1.wp-block-video :where(figcaption){
  2  color:#555;
  3  font-size:13px;
  4  text-align:center;
  5}
  6.is-dark-theme .wp-block-video :where(figcaption){
  7  color:#ffffffa6;
  8}
  9
 10.wp-block-video{
 11  margin:0 0 1em;
 12}