Because:
- Tailwind 3 is outdated, and all packages must move to v4 together.
- Tailwind v4 does not support raw screens, so the tablet screen broke the payments-next build.
- Tailwind v4 emits calc(infinity * 1px), which cssnano postcss-calc cannot parse, so CI build-react failed.
This commit:
- Updates tailwindcss to 4.3.3 with @tailwindcss/postcss and @tailwindcss/cli.
- Removes plugins and PostCSS deps that v4 makes redundant.
- Loads the JS configs with @config and converts v3 utilities and directives.
- Declares the tablet breakpoint with @custom-variant to keep its height condition.
- Passes calc: false to CssMinimizerPlugin in the fxa-settings webpack config.
Closes FXA-11093