typography-font-stinger

name	typography-font-stinger
description	Typography and font-loading specialist for web products — variable fonts, Google Fonts vs Fontsource vs self-host, the FOIT/FOUT/FOFT loading story, font-display semantics, fluid type scales via clamp(), vertical rhythm, and the type-token architecture. Use when the user says "set up fonts", "audit our typography", "fix FOIT/FOUT", "build a type scale", "migrate to next/font", "self-host fonts", "fluid type", "variable fonts", "font performance", or when typography-font-worker-bee is invoked. Do NOT use for typeface selection or brand identity decisions (design-system-worker-bee), per-component application of type tokens (ux-ui-worker-bee), build pipeline font optimization (devops-worker-bee), or persisted user font preferences (db-worker-bee).
license	MIT

Typography Font Stinger

Typography is the invisible infrastructure of every UI. Font loading choices directly impact Core Web Vitals (LCP, CLS), accessibility (WCAG 1.4.4 text resize), and brand consistency. Getting it right in 2026 means navigating variable font subsetting, the font-display decision matrix, fluid clamp() type scales, and the growing split between next/font, Fontsource, and full self-hosting pipelines.

This Stinger encodes the 2026 state-of-the-art for the full technical typographic stack: font loading strategy, variable font configuration, fluid type scale arithmetic, vertical rhythm, and the font-token layer. Read SKILL.md for task routing; follow the specific guide for implementation depth.

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Task routing

Task	Guide
Understand FOIT, FOUT, FOFT, and font-display semantics	guides/00-principles.md
Choose font hosting strategy (next/font vs Fontsource vs self-host)	guides/01-hosting-strategy.md
Configure variable fonts and subsetting	guides/02-variable-fonts.md
Build a fluid type scale with clamp()	guides/03-fluid-type-scale.md
Establish vertical rhythm and line-height	guides/04-vertical-rhythm.md
Author a font token CSS layer	guides/05-font-token-layer.md
Audit and improve font loading performance	guides/06-performance-checklist.md
Happy-path: Next.js + next/font + Tailwind	examples/happy-path-nextjs-font.md
Edge-case: self-hosted variable font with manual subsetting	examples/edge-case-self-hosted-variable.md
CSS typography token skeleton	templates/typography.css.template.md
next/font config template	templates/next-font-config.ts.template.md

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The seven non-negotiables

From the Command Brief, repeated here as guardrails for every implementation:

1. Always specify font-display on every @font-face rule. Browser defaults vary; omitting it causes unpredictable FOIT/FOUT/FOFT across Chrome, Safari, and Firefox. See guides/00-principles.md.
2. Never reference raw px font sizes in component code. All sizes must route through the fluid type-scale token layer. See guides/05-font-token-layer.md.
3. Distinguish FOIT, FOUT, and FOFT. Each has a different font-display remedy; conflating them leads to wrong values. See guides/00-principles.md.
4. Always subset variable fonts. Unsubsetted variable fonts are 300-800 kB; a Latin subset is typically 20-60 kB. See guides/02-variable-fonts.md.
5. Validate next/font usage against the App Router API, not Pages Router. The two APIs differ in import path, options object, and class/variable application. See guides/01-hosting-strategy.md.
6. Express fluid type steps as clamp() expressions, not media-query breakpoint steps. clamp() provides smooth interpolation that breakpoints cannot replicate. See guides/03-fluid-type-scale.md.
7. Keep the font-token file as the single source of truth. Font decisions scattered across globals, components, and Tailwind config produce a system that cannot be audited holistically. See guides/05-font-token-layer.md.

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Scope boundary

In scope	Out of scope - route to
Font loading strategy (next/font, Fontsource, self-host)	Typeface aesthetic selection - design-system-worker-bee
Variable font axes, subsetting, @font-face config	Build pipeline subsetting CI steps - devops-worker-bee
font-display semantics and FOIT/FOUT/FOFT remediation	Per-component type token application - ux-ui-worker-bee
Fluid clamp() type scale arithmetic	LCP font impact analysis in broader CWV audit - seo-aeo-worker-bee
Vertical rhythm and line-height tokens	Persisted user font preference schema - db-worker-bee
Font-token CSS layer (--font-* custom properties)	Brand identity and palette decisions - design-system-worker-bee

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Quick-start checklist

For a standard Next.js 15 App Router + next/font + Tailwind v4 stack:

• Font loading: next/font/google or next/font/local configured in app/fonts.ts
• Font variables applied to :root via className or variable prop on <html>
• No render-blocking <link rel="stylesheet"> for Google Fonts in <head>
• font-display declared (or confirmed via next/font's automatic optional)
• Variable font configured with wght axis range, not discrete weights
• Fluid type scale: all sizes expressed as clamp() CSS custom properties in tokens/typography.css
• Vertical rhythm: line-height multiples stored as tokens
• No raw px font sizes in any .tsx or .css component file
• Font subset: Latin-only for non-multilingual projects (subset: ['latin'] in next/font)

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Research trail: research/research-summary.md | Command Brief: ai-tools/command-briefs/typography-font-worker-bee-command-brief.md