<div class="header">
  <div class="logo">logo</div>
  <div class="menu">
    <a>item</a>
    <a>item</a>
    <a>item</a>
  </div>
</div>

.header {
  display:grid;
  grid-template-columns: 1fr auto 1fr;

  &::after {
    content: ''
  }
}

.menu {
  display:flex;
  gap:1em;
}

* {
  outline:1px solid red;
}