Where to put repetitive styling

[dan3460]

New to tailwind and testing Laravel 8. Where would you put repetitive styling such for a button for example. I thought that i understood to put them in the components file but i get an error when compiling. Here is the styling that I'm testing

.btn {
    @apply h-10 px-5 m-2 text-indigo-100 transition-colors duration-150 bg-indigo-700 rounded-lg focus:shadow-outline hover:bg-indigo-800;
}

here is the error that i get:

(6:5) `@apply` cannot be used with `.focus\:shadow-outline` because `.focus\:shadow-outline` either cannot be found, or its actual definition includes a pseudo-selector like :hover, :active, etc. If you're sure that `.focus\:shadow-outline` exists, make sure that any `@import` statements are being properly processed *before* Tailwind CSS sees your CSS, as `@apply` can only be used 
for classes in the same CSS tree.

I'm confused if this is a base, component or utility.

Thanks for the help.