This version enables the experimental matchVariant feature that comes with tailwindcss v3.1.0. You can now use .cq-w-[240px]:w-12.
IMPORTANT: Make sure that you are not overriding experimental feature. If you want to add another experimental flag, make sure you also add matchVariant: true in your config file. If you don't have the experimental key, it's fine too.
For instance:
{
experimental: ['optimizeUniversalDefaults', 'variantGrouping', 'matchVariant'],
theme: { ....