1. Audit: screenshots of every button, input and card in the product (we had 23 button styles 😱)

1. Audit: screenshots of every button, input and card in the product (we had 23 button styles 😱) 2. Tokens first: colour, spacing, type. Shipped as CSS variables, so old components picked up some changes for free 3. Rebuilt the 10 most-used components, migrated screen by screen 4. Lint rule flags old components in new code It took 5 months, with zero 'design system sprint'. Slow and boring wins.