theme()

theme() is a function that makes it possible to access the theme using dot-config syntax.

.btn-blue {
  background-color: theme('colors.blue.500');
}

Where theme('colors.blue.500') will be compiled to #3b82f6;.

theme() can also be used in rules or shortcuts, or even in utilities:

<button class="bg-blue-400 px-[calc(theme(breakpoints.xl)/2)] py-xl">button</button>