Time-relative pseudo-selectorsThe :past and :future CSS pseudo-classes match prior or upcoming text track cues during media playback.selectorsSelectorslimitedhttps://w3c.github.io/webvtt/#the-past-and-future-pseudo-classeshttps://developer.mozilla.org/docs/Web/CSS/Reference/Selectors/:pastcss.selectors.futurecss.selectors.pasthttps://nowyoucanuse.com/features--time-relative-selectors.html