After I wrote up my Basic CSS Processing Setup that used Lightning CSS, Michael Bishop responded saying he uses PostCSS for essentially the same thing, with a forked repo demonstrating. I think Michael has a good point that PostCSS has a built-in watcher which simplifies the setup nicely. And postcss-preset-env is very similar in spirit, but you don’t get the bundling without another plugin, and you don’t get the minification. So like all things development: it’s a trade-off.
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