Reusable elements built into the platform.
WHAT THEY ARE
Custom elements defined by you, usable as ordinary markup.
WHAT THE PIECES ARE
Custom element definitions Encapsulated internal structure and styling Templates
WHAT ENCAPSULATION PROVIDES
Styles inside not affecting the page, and page styles not affecting inside.
WHY THAT MATTERS
Components can be reused across projects without style conflicts.
WHAT THAT ALSO COMPLICATES
Theming, since page styles do not reach in by default.
WHAT TO PROVIDE FOR THEMING
Defined custom properties the consumer may set.
WHAT THEY SUIT
Components shared across projects or teams Components used in pages built with different frameworks Design system elements
WHAT THEY DO NOT REPLACE
Frameworks, for application structure and state.
WHAT TO BE CAREFUL WITH
Accessibility, which must be implemented deliberately Form participation, which requires specific handling Server-side rendering
WHAT TO CHECK
Keyboard operability and announcement, since encapsulation does not provide them.
