> A modal log in screen is five elements: a shade, a dialog, two labels, two inputs and a button. These are all very easy to name.

Agreed. But why name them at all if the structure is so simple? Keep your simple, understandable structure, colocate your styles with tailwind classes, and avoid the unnecessary cognitive overhead of naming obvious things (is it .username or .user-name?) and linking them with remote styles in a different file.

Not saying it’s the “one true way”, but I don’t think your way is necessarily simpler.