I only found [this page](http://www.impressivewebs.com/css-vertical-align/), explaining vertical-align property of CSS, but it does not work according to this fiddle:

<http://jsfiddle.net/C8ejb/>

important part of the CSS: (is required to post the question)

```
header
{
    display:inline-block;
    height:20%;
    width:100%;
    background:rgba(0,0,0,0.9);
    color:#ccc;
}
    header .header_content
    {       
        display:inline-block;
        background:rgba(255,255,255,0.4);
        vertical-align:middle;  
    }

```

So, can we build a list of conditions where we can actually use vertical-align property, that could save a lot of "why my vertical-align rule is not working?" questions, I guess.

Thanks for any help !