<!DOCTYPE html>
<html>

<body>
  <nav class="navbar">
    <div class="title">My Site</div>
    <ul class="menu">
      <li class="menu-item"><a href="#">Item-1</a></li>
      <li class="menu-item"><a href="#">Item-2</a></li>
      <li class="menu-item"><a href="#">Item-3</a></li>
    </ul>
  </nav>
</body>

</html>
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

.navbar {
  display: flex;
  justify-content: space-between;
  box-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.2);

  .title {
    font-size: 30px;
    font-weight: 700;
    padding: 20px; // height of the navbar; match with padding of 'a'
  }

  .menu {
    display: flex;
    align-items: center;
    margin: 0 10px;
    gap: 10px;

    .menu-item {
      list-style: none;
      font-size: 22px;

      a {
        text-decoration: none;
        color: black;
        padding: 20px; // vertical positioning of border-bottom line
        opacity: 0.7;
        border-bottom: 5px solid transparent;
      }

      &:hover {
        a {
          opacity: 1;
          border-bottom: 5px solid orange;
          border-bottom-left-radius: 5px;
          border-bottom-right-radius: 5px;
        }
      }
    } //menu-item
  } //menu
} //navbar
View Compiled 
// CSS Only //

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