Resposive Meta tag for your website

HTML

<meta name="viewport" content="width=device-width">

Although I see this is recommended a lot:

HTML

<meta name="viewport" content="width=device-width, initial-scale=1">

This means that the browser will (probably) render the width of the page at the width of its own screen. So if that screen is 320px wide, the browser window will be 320px wide, rather than way zoomed out and showing 960px (or whatever that device does by default, in lieu of a responsive meta tag).