reduce intro text

[kohlhase]

On the main page we have too much text (people will not read that)
I think we can put the detail about ranges

To add a numeric range insert \range{lower}{high} or \relrange{base}{deviation} (this adds a interval from [base - base*deviation%, base + base*deviation%]) in your search query. 

into a background explanation page.
Incidentaly, the link on ...more is not very helpful. We should have a good front-end explanation page there instead.

[typohnebild]

Here is may proposal for that, there is now a more information page that contains all this text.

And we have now such a sticky header, maybe move the buttons from #12 somehere in that header?