#web-components

Show me how to create a simple, self-contained Web Component for a custom button. The component should use a Shadow DOM to encapsulate its styles and markup. It should also have a `disabled` attribute that can be toggled. Use vanilla JavaScript (ES6 classes).

Build a framework-agnostic design system with Lit. Components: 1. Custom elements with @customElement decorator. 2. Reactive properties with @property. 3. Shadow DOM for style encapsulation. 4. Slots for content projection. 5. CSS custom properties for theming. 6. Event dispatching with CustomEvent. 7. Form-associated custom elements. 8. TypeScript for type safety. Package as npm library, document with web-component-analyzer, and test with @web/test-runner.