/**
 * Viewport-size media queries for frozen shadow previews.
 *
 * A shadow root has no viewport of its own, so `@media (max-width: …)` inside
 * a frozen document is judged against the editor window instead of the frame:
 * a 480px frame in a 1600px editor draws its desktop layout. The frame box is
 * a named size container (`:host`), and size conditions are rewritten into
 * container queries on it. Conditions that are not about the viewport size
 * (print, prefers-*, hover, device-*) stay media queries, and a query that
 * cannot be split that way is kept as written and reported.
 */
/** The container name the frozen preview host carries; app containers never answer to it. */
export declare const PREVIEW_VIEWPORT_CONTAINER = "pygmalion-viewport";
export interface PreviewMediaScope {
    cssText: string;
    /** Size-dependent media the rewrite could not express; the frame may draw at the editor window's size. */
    issues: string[];
}
export type PreviewMediaConversion = {
    kind: 'keep';
} | {
    kind: 'never';
} | {
    kind: 'container';
    condition: string;
} | {
    kind: 'nested';
    media: string;
    condition: string;
} | {
    kind: 'unsupported';
    reason: string;
};
/** Converts one `@media` prelude, or says why it stays as written. */
export declare function convertPreviewMediaPrelude(prelude: string): PreviewMediaConversion;
/**
 * Rewrites the size conditions of every `@media` rule, at any nesting depth,
 * into container queries on the preview viewport. Comments and strings are
 * copied untouched.
 */
export declare function scopeViewportMediaToPreviewContainer(cssText: string): PreviewMediaScope;
/**
 * The media condition of a `<style media>` or `<link media>`: true when it
 * depends on the viewport size, which a shadow root cannot answer.
 */
export declare function mediaListDependsOnViewportSize(media: string): boolean;