Banner
A full-width message pinned above the header, for something account- or system-wide. The test is whether it would still matter on another page: yes and it is a Banner, no and it is an Alert. There is no success variant — “it worked” is a Toast — and no icon prop either: the icon appears only when a BannerIcon is composed in.
Usage
Examples
All colors
primary (dark) and secondary (light) are the neutral bars and carry no icon of their own; destructive, info and warning each bring one.
With description
A description earns its place by adding the consequence — here the node version the feature needs — never by restating the title.
With inline link
A BannerLink inside the title, for when the action belongs in the sentence. Use the inline link or the trailing buttons, never both.
Long text
Two lines is the ceiling, after which the text truncates into a tooltip. One line is what to aim for.
Custom icon
BannerIcon’s icon prop overrides the variant default, or gives primary and secondary the icon they otherwise lack — which is how an announcement gets its megaphone.
With actions
Trailing buttons in BannerControls, small and never solid, labelled with the verb that follows: “Renew”, not “Learn more”.
Closable
BannerClose where the reader may dismiss it. Leave it off while the condition still holds, since a banner is meant to outlast a page view.