iOS Zoom Lock

Fields keep the 13px control text on phones. iOS and iPadOS Safari zoom into a focused field whose text is under 16px and stay zoomed after it loses focus. This is the recommended fix when that zoom gets in the way; max-md:text-base on a field is the alternative when you'd rather have 16px text on phones.

When an input, textarea, select or contenteditable element gets focus, the viewport meta gains maximum-scale=1 (an existing maximum-scale is replaced). When focus leaves text entry, the meta gets its original content back exactly. Moving from one field to the next keeps the lock, so the meta doesn't flicker. Buttons, checkboxes, radios, ranges, file and colour inputs don't lock.

Outside a focused field the viewport is untouched, so pinch zoom works as before. Safari still allows pinch zoom while a field is focused, since it ignores maximum-scale for gestures; a home-screen web app honours it, so there pinch zoom waits until the field loses focus.

Off by default and imported by nothing else. It runs only on iPhone, iPad and iPod, including iPads that report a desktop Mac user agent (MacIntel with more than one touch point). devices="touch" adds every coarse pointer; other browsers don't zoom on focus, so this is rarely needed.

Everything runs in effects, so server rendering is unaffected. Without a viewport meta, a temporary one is added while a field is focused and removed afterwards. Several mounted locks share one listener set, and the original content comes back when the last one unmounts or its enabled turns off, focused or not. A field removed while focused fires no blur; the next touch restores the meta.