/**
 * @license
 * Copyright Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
/** @fileoverview Internal implementations of SafeStyleSheet. */
import '../environment/dev.js';
/**
 * A complete CSS style sheet, safe to use in style contexts in an HTML
 * document or DOM APIs.
 *
 * @final
 */
export declare class SafeStyleSheet {
    private readonly privateDoNotAccessOrElseWrappedStyleSheet;
    private constructor();
    toString(): string;
}
/**
 * Builds a new `SafeStyleSheet` from the given string, without enforcing
 * safety guarantees. This shouldn't be exposed to application developers, and
 * must only be used as a step towards safe builders or safe constants.
 */
export declare function createStyleSheetInternal(value: string): SafeStyleSheet;
/**
 * Checks if the given value is a `SafeStyleSheet` instance.
 */
export declare function isStyleSheet(value: unknown): value is SafeStyleSheet;
/**
 * Returns the string value of the passed `SafeStyleSheet` object while ensuring it
 * has the correct type.
 */
export declare function unwrapStyleSheet(value: SafeStyleSheet): string;