CSS :current 擬似クラス

:current {
  /* ... */
}

:current(<compound-selector-list>) {
  /* ... */
}

p::search-text {
  color: white;
  background-color: purple;
}

p::search-text:current {
  background-color: crimson;
}

<p>
  Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec finibus est
  eget eros congue pellentesque. Etiam a augue accumsan, scelerisque nisl sit
  amet, lobortis nulla. Aliquam condimentum eu orci eu elementum. Donec
  porttitor quam et posuere commodo. Mauris rhoncus diam a scelerisque molestie.
  Integer sollicitudin risus dui, ut sagittis lorem laoreet eget. Duis eget
  pretium enim. Morbi tristique, diam sit amet gravida finibus, metus ex
  tincidunt nibh, ac volutpat urna purus et arcu. Donec risus risus, semper vel
  purus sit amet, gravida vestibulum est. Sed et tristique urna. Nam vel mi eget
  nisi consectetur elementum. Aenean faucibus aliquam cursus. Morbi posuere
  tincidunt velit, et sagittis quam sagittis in. Nam eget ante ultrices, auctor
  dui vel, euismod lacus. Vivamus tincidunt, sem ac sodales aliquet, tortor
  tortor consequat diam, nec tempor mi dui vel eros. Aliquam ac erat et metus
  egestas scelerisque.
</p>

html {
  font-family: "Helvetica", "Arial";
}

p {
  font-size: 1.5rem;
  line-height: 1.5;
  width: 90%;
  margin: 0 auto;
}

@layer no-support {
  body::before {
    background-color: wheat;
    display: block;
    text-align: center;
    padding: 1em 0;
  }
  @supports not selector(::search-text) {
    body::before {
      content: "このブラウザーは ::search-text 擬似要素に対応していません。";
    }
  }
  @supports not selector(:current) {
    body::before {
      content: "このブラウザーは :current 擬似要素に対応していません。";
    }
  }
}

::search-text {
  background-color: purple;
  color: white;
  text-shadow: 1px 1px 1px black;
}

::search-text:current {
  background-color: crimson;
  text-decoration-line: underline;
  text-decoration-color: yellow;
  text-decoration-thickness: 3px;
}

:current(p, span) {
  background-color: yellow;
}

<video controls preload="metadata">
  <source src="video.mp4" type="video/mp4" />
  <source src="video.webm" type="video/webm" />
  <track
    label="English"
    kind="subtitles"
    srclang="en"
    src="subtitles.vtt"
    default />
</video>