Allright update! I now know how to make a css, how to get it into defold an where to put it.
For my brothers and sisters with the same starting problems:
- you make a css sheet with your editor and simply save it with .css as ending (e.g: style.css)
- you get the sheet into defold like most things: with drag and drop
- in your project Settings you go down to the html5 Settings now you can now add the Custom css
Still turns out I’m using the code wrong or it’s simply not meant to do what I want it to 
So no Advance here
Alright next EDIT:
I found @Pkeod s JS File exactly for my Problem magic link
How can I add the JS to the HTML file’s script area as it says? I can’t find anything in the html5 project settings where I could add the JS 
Sorry for any english mistakes