Media query works on chrome but firefox picks up wrong resolution / query

Question

So here is my question on Mozilla support:

So I am testing my website in the Responsive Design-modus and there is no problem with the the CSS. But when I am at my phone the site shows me the CSS of desktop. He zooms in because of the viewport (I think). I do not know if this is the problem.

What I tried with the CSS:

@media screen and (min-width: {PixelNumber}px) { /* CSS stuf */ } 
/*or*/ 
@media only screen and (min-width: {PixelNumber}px) { /* CSS stuf */ }

This is my html meta tag:

<meta name="viewport" property="viewport" content="width-device-width, initial-scale=0.9">

Click here to view my site

On chrome: And on firefox

Answer 1

width-device-width in your viewport tag should be width=device-width