Superposition is free and works on Windows, Mac & Linux.

Extract colors, typography, spacing, border radii, shadows and motions from sites, and exports them to CSS, SCSS, JavaScript and Adobe XD with a Plugin for XD. Sketch and Figma plugins are coming soon.

The Superposition plugin for Figma lets you extract design tokens from live websites and use them directly in your designs on Figma. Design using the colors, typography, border-radius, shadows and images from sites.