import { type Observer, type Reference } from "@knyt/artisan";
/**
 * @internal scope: workspace
 */
/**
 * ### Private Remarks
 *
 * This is not a reactive controller, as it does not react to host updates.
 * It only responds to changes in the root reference.
 * Its purpose is to manage adopted style sheets for a root,
 * separating style sheet adoption from controller logic.
 * This makes its role clearer, especially in the context of HMR.
 */
export declare class StyleSheetAdoptionAdapter implements Observer<ShadowRoot | Document | null> {
    #private;
    constructor({ root }: {
        root: Reference.Maybe<ShadowRoot | Document>;
    });
    /**
     * Called when the host's root changes.
     *
     * @internal scope: module
     */
    next(root: ShadowRoot | Document | null): void;
    /**
     * Adds the given style sheet to the adopted style sheets.
     * If the style sheet is already present, this is a no-op.
     */
    adoptStyleSheet(input: StyleSheetAdoptionAdapter.Input): void;
    /**
     * Removes the first occurrence of the given style sheet from the adopted
     * style sheets.
     */
    dropStyleSheet(input: StyleSheetAdoptionAdapter.Input): void;
    /**
     * Checks whether the given input is already adopted.
     */
    hasStyleSheet(input: StyleSheetAdoptionAdapter.Input): boolean;
    /**
     * Drops all adopted style sheets.
     */
    clearStyleSheets(): void;
}
export declare namespace StyleSheetAdoptionAdapter {
    type Input = CSSStyleSheet | {
        toCSSStyleSheet: (CSSStyleSheetConstructor?: typeof CSSStyleSheet) => CSSStyleSheet;
    };
}
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