Variable viewports`Const`

viewports: {
    viewportSmall: "--tile--viewport-small";
    viewportMedium: "--tile--viewport-medium";
    viewportLarge: "--tile--viewport-large";
    viewportXlarge: "--tile--viewport-xlarge";
} = ...

The custom property behind every viewport token.

Narrowed to literals, so the design system contract can name the tokens and the custom properties they resolve to.