“Before the new engine, we always had to be careful with CSS file size in development, and one of the biggest trade-offs we had to make was carefully limiting the color palette.”
Tailwind generated every possible class and made you purge the rest. The Just-in-Time engine flips that and only builds what your markup uses. Now it’s the default, and the whole palette comes back. It took until v3 to fix a size problem Tailwind’s own design created.