Typography

Setting Type

Default posture: one family, a short closed scale, unitless leading banded by role, a capped measure — and hierarchy carried by weight and grey value before size. Most product UI never needs a display size at all. Benji Taylor's site sets its article h1 at 15px/600, h2 at 14px/560 and body at 14px/460 on a 20px line-height with -0.09px tracking, and 19px is the largest type anywhere on it; the page still reads as ordered because weight and value do the work size normally does. Reach for a larger step only once weight and grey have run out. This skill sets type for legibility and rhythm; whether the family expresses the brand belongs to brand-identity, which picks the face and never renegotiates the scale, leading, measure or numerals fixed here. The words inside the type are ui-copy. Contrast ratios have exactly one owner and it is color.

Detect the styling idiom before proposing a single declaration. Read how the project already expresses type — Tailwind utilities, a @theme block, CSS custom properties, CSS Modules, styled-components, generated tokens — and write every fix in that same mechanism. A type fix is never a reason to bolt a second styling system onto a codebase; if the scale lives in @theme, the new step goes there, not in a one-off style prop.

Quick Reference

Core Principles

1. Carry hierarchy with weight and grey value before you carry it with size. Size inflation is what makes an app look like a poster; weight and value separate roles without spending vertical space. Ship a near-flat scale where the whole body sits at 14–16px and roles separate at 460 / 560 / 600, with secondary text stepping down in value rather than in size. Exception: marketing surfaces, where marketing-pages explicitly buys a display step for the hero.
2. Every font-size traces back to a closed scale. Ad-hoc values decay fast: each new component invents a size that is nearly, but not exactly, an existing one. Define six to eight steps — a ratio-derived set (1.2 on a 16px root) or Tailwind's text-* both qualify. Exception: a wordmark or one optical fix on a single headline, which gets a comment saying why it is off-scale.
3. Write line-height unitless and band it by role. A hard-coded 24px leading detonates on the first size change or user zoom. Body copy reads at 1.5–1.6; display and headings sit near 1.1. Exception: single-line boxed labels — buttons, badges, table cells — where the box sets the height and line-height: 1 (plus text-box trimming) is correct.
4. Cap the reading measure near 65ch. Past roughly 75 characters the eye loses its return path and reading turns into work; max-width: 65ch states the intent directly, and Tailwind's max-w-prose is defined as exactly 65ch. This is a house default, not a standards number. Exception: table cells, code blocks and dense grids, where the column, not the measure, sets the width — dense-ui owns those.
5. Apply tracking only at the two ends of the scale. Large glyphs are fit too loosely and small capitals too tightly; body sizes are already fit for reading. Use roughly -0.015em on display steps and 0.06em on small uppercase labels, and write it in em so it scales with the text. Exception: none for body copy — a single letter-spacing value applied uniformly across a whole scale is a finding, not a style.
6. Put tabular-nums on any number that changes in place. Most fonts draw a narrow 1 and a wide 4, so a live timer, price, counter or ticking total shoves its neighbours on every update. Reach for font-variant-numeric: tabular-nums. Exception: numbers inside running prose, where proportional figures read better and nothing re-renders.
7. Ask for a CSS property, never the raw axis or feature tag. High-level properties still do something sensible when a fallback font renders; a raw tag aimed at a font that never loaded does nothing at all. Write font-weight: 620, font-optical-sizing: auto, font-variant-numeric: tabular-nums. Exception: things with no property of their own — a custom axis such as Fraunces' "WONK" 1, or a numbered stylistic set such as "ss03" 1.
8. Forbid synthesized styles. Ask for a bold or italic that was never loaded and the browser fabricates one by thickening or shearing the real glyphs, which reads as a quietly ugly render rather than an obvious bug. Declare font-synthesis: none once at the root. Exception: a deliberate system-stack product that ships no font files — then synthesis is all there is, and the decision belongs in a comment.
9. Switch typeface for emphasis before you add a weight. When body weight already carries hierarchy, another bold flattens the page; a second face marks the emphasis without competing. Benji's articles emphasise by switching to Newsreader italic at opsz 10 rather than bolding. Exception: single-family products, where bold is the only tool — and italic never becomes UI hierarchy, since italic means citation and linguistic stress, not importance.
10. Serve woff2, subset it, and reserve the space it will occupy. woff2 carries Brotli compression and every browser that matters accepts it; ttf/otf are uncompressed desktop containers. Preload the one face above the fold and metric-match the fallback so the swap does not shift layout. Exception: woff when a written requirement names a genuinely ancient browser.

Non-integer variable weights are legitimate — 460, 560 and 430 are real values in a variable font, and they are how a near-flat scale gets its separation. One floor restated from Tier 0: mobile input text never drops below 16px, and maximum-scale=1 is a WCAG 1.4.4 failure, never the fix; touch-input holds the rest of the iOS Safari quirks.

Smell / Fix

Reporting a Type Pass

Group findings by file. Each is one line: where it is, what is wrong, the corrected declaration in the project's own idiom, and the principle number it serves. Stay silent on what the code already gets right, and fix with the smallest possible diff — type work does not restructure markup unless an expandable truncation genuinely needs an extra element.

Checklist

• Hierarchy separates by weight and value first; size is the last resort
• Every font-size traces to a closed scale, exceptions commented
• line-height unitless — 1.5–1.6 body, ~`1.1display,1` on boxed single-line labels
• Reading columns capped near 65ch
• Tracking only at the extremes, written in em; body is 0
• tabular-nums on every value that updates in place
• Weights and features go through font-weight / font-variant-*; raw tags only for custom axes and numbered sets
• font-synthesis: none declared; no fabricated bold or italic anywhere
• Emphasis uses a second face or a real weight, never italic-as-hierarchy
• Fonts are woff2, subset, preloaded above the fold, with a metric-matched fallback
• Mobile input text is 16px or larger; no maximum-scale=1
• Source strings keep human casing; any shouting is done by CSS
• Every truncation offers a route to the full string
• Logical properties plus lang / dir wherever direction can vary