Design Principle
Typeface differences need a clear purpose; decorative mixing can increase reading cost.
Principle
Typeface differences need a clear purpose; decorative mixing can increase reading cost.
Design action
Default to a clear sans-serif; add contrast fonts only at heading level when brand expression needs it, and use monospaced or tabular numerals for data.
Examples
Positive example: Brand pages, portfolios, data products, and knowledge content. Counterexample: Several decorative typefaces appear on one screen.
Apply when
Brand pages, portfolios, data products, and knowledge content. Numeric or technical interfaces need tabular clarity.
Source notes
Source note: Synthesized from W3C WCAG 2.2, Apple Accessibility, IBM Carbon Accessibility, and accessibility practices in major design systems. WCAG 2.2: https://www.w3.org/TR/WCAG22/ WCAG Contrast Minimum: https://www.w3.org/WAI/WCAG21/Understanding/contrast-minimum.html WCAG Non-text Contrast: https://www.w3.org/WAI/WCAG22/Understanding/non-text-contrast.html Apple HIG Accessibility: https://developer.apple.com/design/human-interface-guidelines/accessibility Carbon Accessibility Overview: https://carbondesignsystem.com/guidelines/accessibility/overview/
Agent Directive
Default to a clear sans-serif; add contrast fonts only at heading level when brand expression needs it, and use monospaced or tabular numerals for data.