Viewport meta
HTML meta tag that controls how a mobile browser scales content. <meta name="viewport" content="width=device-width, initial-scale=1">. Required for responsive design — without it, Safari zooms out to desktop-rendering width.
Apple introduced the concept with the iPhone in 2007. Default mobile viewport ~980 px (desktop-fit rendering). With width=device-width, the viewport matches device pixel width → CSS media queries work as expected. maximum-scale=1, user-scalable=no = anti-pattern (breaks pinch-to-zoom, accessibility issue). viewport-fit=cover + safe-area-inset CSS for notched displays (iPhone X+). Google Lighthouse + responsive-design test tools check that viewport meta exists.