I have a div that I want to position at 10% below the beginning of the page. If I use this CSS rule:

```
#div-block{
   margin-top: 10%;
}

```

The div's computed margin-top is approximately 192px (my screen resolution is 1920 x 1080) so all browsers I tested are using the page's width (rather than height) for calculating the value. 

How can I do to make them calculate using the height (suppose 1080px) using only CSS?