Components

Which components the system carries: its inventory, picked from the catalogue.

The five answers

Question	Answer	Why
Which component families does it need?	Actions, forms, feedback, overlays, layout and navigation	Forms, steps and feedback are all a public service needs.
How far does the inventory reach?	Only what today's screens use	Only the parts in use, each tested with assistive technology.
How does a component earn its place?	It works for everyone, with any device and assistive technology	A component joins only when it works with any device and assistive technology.
When does a component get another look?	Only when the meaning changes	One clear way to do each thing.
Where do components do the most work?	Forms and steps	Components do their work in forms and steps.

When to use what

Situation	Use	Not	Why
No component in the inventory fits	a native HTML element with a label and a hint	a custom widget that needs hover, drag or precise pointing	Native elements work with every assistive technology without extra work.