<section>
  <nav>
    <a href="#a">Link A</a>
    <a href="#b">Link B</a>
    <a href="#c">Link C</a>
  </nav>
</section>

@import url("https://fonts.googleapis.com/css2?family=Inter:ital,opsz,wght@0,14..32,100..900;1,14..32,100..900&display=swap");

body {
  font-family: "Inter", sans-serif;
  display: grid;
  place-items: center;
  height: 100vh;

  a {
    display: block;
    padding: 1em;
  }

  nav {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
  }
}

a {
  transition: opacity 0.2s;
}

:has(> a:hover) > a:not(:hover) {
  opacity: 0.2;
}