title: vertical-align does not work
body: <p>I have this HTML:</p>
  
  <pre><code>&lt;div class="title_right mid_center top_menu"&gt;
    &lt;a class="btn btn-app" href="/Home/ComoFunciona"&gt;
    &lt;a class="btn btn-app" href="/Home/Tarifas"&gt;
    &lt;a class="btn btn-app" href="/Home/Contacto"&gt;
    &lt;a class="btn btn-app" href="/Security/Account"&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>The CSS is: </p>
  
  <pre><code>.page-title .title_right {
    width: 55%;
    float: left;
    display: block;
  }
  
  .mid_center {
      width: 370px;
      margin: 0 auto;
      text-align: center;
      padding: 10px 20px;
  }
  
  div.top_menu {
      height: 167px;
      vertical-align: middle;
  }
  </code></pre>
  
  <p>How can I center those buttons vertically? I don't want to patch it using padding.</p>