about viewport meta tag

description

Tells the browser that this webpage is optimized for mobile, changes the logical window size used when displaying a page on mobile browsers.
Include width=device-width to match the screen's width in device-independent pixels, and please ensure your page is accessible by not disabling user scaling.

content example

The advised parameters to correctly support responsive design is the following:
<meta name="viewport" content="width=device-width,initial-scale=1">