Just downloaded the Bootstrap 4 Dashboard template and are trying to add a form to the top search bar. When I do this the search bar shrinks and loses it's design. 

[Bootstrap 4 Dashboard template](http://getbootstrap.com/docs/4.0/examples/dashboard/)

It's probably down to html/CSS by I can't figure out how to accomplish this without breaking up the design, not that familiar with the new and added CSS in Bootstrap 4.

Tried this, but like I said, the form shrinks to the center:

```
<nav class="navbar navbar-dark sticky-top bg-dark flex-md-nowrap p-0">
  <a class="navbar-brand col-sm-4 col-md-2 mr-0" href="#">My Site</a>
    <form action="search.php" method="POST">
      <input class="form-control form-control-dark w-100" type="text" placeholder="Search">
    </form>
  <ul class="navbar-nav px-3">
    <li class="nav-item text-nowrap">
      <a class="nav-link" href="logout.php">Log out</a>
    </li>
  </ul>
</nav>

```