The following container should be vertically centered...:
<div style="
position:fixed;
top:0;
bottom:0;
margin:auto;
background-color:red;
width: 50px;
height:50px;
z-index:555;
"></div>
...and it is in all major browsers except Android. Is there any way to vertically center this in Android as well? It displays in top left corner.
Have you tried
top: 50%; margin-top: -25px;