Tailwind - absolute vs relative position dropdown

im having a problem trying to set de position of a dropdownlist. I want it to be on top of everything, but when it comes into a relative positioned element, it just goes behind it. Here is a code example of what I mean.

html example:

  <div class="dropdown  relative">
    <button class="bg-gray-300 text-gray-700 font-semibold py-2 px-4 rounded inline-flex items-center">
      <span class="mr-1">Dropdown</span>
      <svg class="fill-current h-4 w-4" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9.293 12.95l.707.707L15.657 8l-1.414-1.414L10 10.828 5.757 6.586 4.343 8z"/> </svg>
    </button>
    <ul class="dropdown-menu absolute hidden text-gray-700 pt-1">
      <li class=""><a class="rounded-t bg-gray-200 hover:bg-gray-400 py-2 px-4 block whitespace-no-wrap" href="#">One</a></li>
      <li class=""><a class="bg-gray-200 hover:bg-gray-400 py-2 px-4 block whitespace-no-wrap" href="#">Two</a></li>
      <li class=""><a class="rounded-b bg-gray-200 hover:bg-gray-400 py-2 px-4 block whitespace-no-wrap" href="#">Three is the magic number</a></li>
    </ul>
  </div>
  <div class="dropdown relative">
    <button class="bg-gray-300 text-gray-700 font-semibold py-2 px-4 rounded inline-flex items-center">
      <span class="mr-1">Dropdown</span>
      <svg class="fill-current h-4 w-4" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 20 20"><path d="M9.293 12.95l.707.707L15.657 8l-1.414-1.414L10 10.828 5.757 6.586 4.343 8z"/> </svg>
    </button>
    <ul class="dropdown-menu absolute hidden text-gray-700 pt-1">
      <li class=""><a class="rounded-t bg-gray-200 hover:bg-gray-400 py-2 px-4 block whitespace-no-wrap" href="#">One</a></li>
      <li class=""><a class="bg-gray-200 hover:bg-gray-400 py-2 px-4 block whitespace-no-wrap" href="#">Two</a></li>
      <li class=""><a class="rounded-b bg-gray-200 hover:bg-gray-400 py-2 px-4 block whitespace-no-wrap" href="#">Three is the magic number</a></li>
    </ul>
  </div>

</div>

css:

.dropdown:hover .dropdown-menu {
  display: block;
}

live: https://codepen.io/lcsalt/pen/MWpPvJp

How can I ensure that the list is above everything, no matter what? i tried with z-index but didn't help.