Tailwind
Why Tailwind need tailwind.config.js postcss.config.mjs such two config file
The first is for tailwind itself, tailwind uses postcss internally. Postcss is a tool for transforming CSS with JS plugins.
Tailwind uses a rem-based spacing system
1 = 0.25rem = 4px
1rem = 16px
rem means root em, relative to the root element's font size which is defined in the <html> element as font-size: 16px;
arbitrary values
lg:h-[60px]