The text-emphasis CSS property provides a typographic mechanism for marking or highlighting individual characters with small marks — commonly used in East Asian typography to indicate emphasis or pronunciation cues. Unlike simple color or weight changes, these marks are rendered as distinct glyph-like annotations that sit adjacent to or above the base text, giving readers a visual cue tied to specific characters rather than the whole run. Because they are conceptual annotations rather than content, they are intended to aid readability and meaning without altering the underlying text content.

Rendering and placement of emphasis marks are sensitive to the writing direction and orientation of the text. For example, vertical text flows will position emphasis marks differently than horizontal flows, and implementations will consult settings such as writing-mode when calculating where to draw the marks relative to glyphs. Emphasis marks are applied at the inline level, so they follow the same inline layout model as the characters they annotate and are repeated per character (or per cluster as the user agent decides), rather than being a single decoration applied to an entire element.

When designing with emphasis marks, consider how they interact visually and functionally with other typographic styling. They are distinct from underlines, overlines, and other line-based ornaments created by text-decoration, so combining both can produce visual clutter or layering effects that need careful spacing and contrast. Likewise, overall type metrics and legibility are influenced by the element’s font settings (size, line-height, and variant choices), since the relative size and placement of emphasis marks are perceived in relation to the base glyphs. Finally, because emphasis marks are presentation-only, keep accessibility and content semantics in mind: they should not be relied on as the sole method to convey essential information that assistive technologies might not convey.