Typography

Human uses a dual-typeface system: Avenir for interface text and Geist Mono for code. The type scale follows a modular progression optimized for readability at every size.

Typefaces

Avenir (UI Text)

Avenir Next is the primary typeface across all surfaces — web, iOS, Android, and documentation. It provides clean, geometric letterforms with excellent readability at small sizes.

Font stack: 'Avenir Next', 'Avenir', system-ui, -apple-system, sans-serif

Geist Mono (Code)

Geist Mono is used for code blocks, terminal output, and monospaced content. It features programming ligatures and clear distinction between similar characters (0/O, 1/l/I).

Font stack: 'Geist Mono', 'SF Mono', 'Fira Code', 'Cascadia Code', monospace

Type Scale

Token	Size	Line Height	Weight	Usage
text.xs	12px (0.75rem)	1.5	400	Captions, badges, metadata
text.sm	14px (0.875rem)	1.5	400	Secondary text, table cells
text.base	16px (1rem)	1.6	400	Body text, form inputs
text.lg	18px (1.125rem)	1.5	500	Subtitles, emphasized body
text.xl	20px (1.25rem)	1.4	600	Card titles, section headers
text.2xl	24px (1.5rem)	1.3	600	Page section titles
text.3xl	30px (1.875rem)	1.25	700	Page titles
text.4xl	36px (2.25rem)	1.2	700	Hero subtitles
text.5xl	48px (3rem)	1.1	700	Hero headlines

Font Weights

Token	Value	Usage
weight.regular	400	Body text, descriptions
weight.medium	500	Emphasized body, labels
weight.semibold	600	Titles, buttons, nav items
weight.bold	700	Headlines, strong emphasis

Letter Spacing (Tracking)

Token	Value	Usage
tracking.tight	-0.025em	Headlines, display text
tracking.normal	0em	Body text
tracking.wide	0.05em	All-caps labels, badges

Usage Roles

Headings

h1 {
  font-size: var(--hu-text-3xl);
  font-weight: var(--hu-weight-bold);
  letter-spacing: var(--hu-tracking-tight);
}
h2 {
  font-size: var(--hu-text-2xl);
  font-weight: var(--hu-weight-semibold);
}
h3 {
  font-size: var(--hu-text-xl);
  font-weight: var(--hu-weight-semibold);
}

Body

p {
  font-size: var(--hu-text-base);
  line-height: 1.6;
  color: var(--hu-text);
}
.secondary {
  font-size: var(--hu-text-sm);
  color: var(--hu-text-muted);
}

Code

code {
  font-family: var(--hu-font-mono);
  font-size: var(--hu-text-sm);
}
pre code {
  font-size: var(--hu-text-xs);
  line-height: 1.6;
}

Cross-Platform Mapping

CSS Variable	Swift	Kotlin	C
--hu-text-base	HUTokens.textBase	HUTokens.textBase	N/A (terminal)
--hu-weight-semibold	.semibold	FontWeight.SemiBold	HU_COLOR_BOLD
--hu-font-mono	Font.custom("GeistMono", ...)	FontFamily.Monospace	N/A

Accessibility

• Minimum body text size is 16px (1rem) for comfortable reading
• Line heights are tuned per size — larger text uses tighter leading
• letter-spacing: var(--hu-tracking-wide) is applied to all-caps text for legibility
• Font weight never drops below 400 for body text