While iOS 13 introduced the system font , iOS 15.4 and related updates refined how these fonts are accessed and rendered:
Safari 15.4 (bundled with iOS 15.4) added support for the ic unit, which is equivalent to the width of a specific glyph in the current font, aiding in more precise web layouts. ios 15.4 fixed space -font- download
A , often called a monospaced or fixed-pitch font, is a typeface where every character occupies the exact same amount of horizontal space. Unlike standard proportional fonts (where an "i" is narrower than a "w"), fixed-width fonts ensure that text aligns vertically in columns—a feature critical for code and structured data. iOS 15.4 Fixed-Width Font Features While iOS 13 introduced the system font , iOS 15
System apps like Apple Mail allow users to view messages in fixed-width fonts to maintain the alignment of text intended for table-like structures. How to Download and Install Fixed-Width Fonts iOS 15