SLDS (Salesforce Lightning Design System) is a CSS framework for building interfaces that match Salesforce's Lightning Experience without writing custom CSS, covering icons, color palettes, fonts, and components.
It's deliberately implementation-agnostic, no specific JS framework required, and the newer SLDS 2 separates structure from visual design using styling hooks (CSS custom properties), enabling deep theming and full dark mode support without forking the underlying component markup.
Developers building Salesforce-integrated apps or Visualforce/Lightning pages who need pixel-accurate Salesforce styling without hand-rolling CSS.
SLDS 2's styling-hooks architecture is worth studying specifically as a model for theming systems that need deep customization without breaking component structure.
Salesforce's own design system for consistent interfaces on its platform.
