Setting the minimum zoom amount for viewing an html page in browser

I've tried adding

@viewport {
/* Keyword value */
min-zoom: auto;

/* <number> values */
min-zoom: 0.8;
width: device-width;

}

and

body {
     width: 1500 px;
}

To my css document

And adding the meta tag to my html

<meta name="viewport" content="width=device-width, initial-scale=1.00, maximum-scale=2.00, minimum-scale=0.80">

And all of it seems to do nothing. The webpage can still zoom in and out just as it did before.

Is there anything else I need to add other than these things?

I'm using the firefox browser