<div class="menu">
  <div class="right">
    <slot name="right" />
  </div>
  <slot />
</div>

<style>
  div.right {
    position: absolute;
    right: 0;
    text-align: right;
  }

  div.menu {
    background-color: #222;
    margin: 0;
    user-select: none;
    display: flex;
    flex-direction: row;
  }
</style>