Design AtlasLowercase text has ascenders (b, d, h, l) reaching up and descenders (g, j, p, q, y) reaching down, giving each word a varied silhouette that readers use for fast word-shape recognition. Set everything in caps and every letter becomes the same height — that silhouette disappears, and the letters read as pressed together, more crowded than they actually are.
That's why UI labels, badges, and eyebrow text set in all caps conventionally pair with positive `letter-spacing` (typically `0.05em–0.15em`). Capitals are already a visually loud, attention-grabbing form; widening the tracking gives them room to breathe and reads as calmer and more considered.
This convention is specific to case-based scripts like Latin and Cyrillic. Hangul has no case distinction at all, so "all caps" isn't a concept that applies to it — in a mixed Korean/English label, it's natural to apply `text-transform: uppercase` and tracking only to the Latin portion and leave the Hangul untouched.
When to use
Pair positive tracking with almost any short all-caps text — badges, eyebrows, buttons. Avoid setting a whole body paragraph in caps; legibility drops sharply.