Substack UI Skills Opinionated constraints for building Substack-style interfaces with AI agents. When to Apply Reference these guidelines when: - Building light-mode interfaces - Creating Substack-inspired design systems - Implementing UIs with Inter font and 4px grid Colors - SHOULD use light backgrounds for primary surfaces - MUST use as page background ( ) - SHOULD reduce color palette (currently 15 colors detected) - MUST maintain text contrast ratio of at least 4.5:1 for accessibility Semantic Tokens | Token | HEX | RGB | Usage | |-------|-----|-----|-------| | | #FFFFFF | rgb(255,255,2…