import { Nullable } from '../../../types/general';
import { SanitizeStrategy } from '../core/sanitize-strategy';
/**
 * CSS / style sanitization strategy.
 *
 * - Strips all HTML elements
 * - Preserves text nodes
 * - Blocks dangerous CSS patterns (expression(), javascript:)
 */
export declare class StyleSanitizeStrategy extends SanitizeStrategy {
  protected readonly allowedTags: ReadonlySet<string>;
  protected readonly preserveTextContent: boolean;
  /**
   * @param {Node} node - Node to sanitize.
   * @param {Document} doc - document reference.
   * @returns {Nullable<Node>} - Sanitized node
   */
  execute(node: Node, doc: Document): Nullable<Node>;
  /**
   * @param {string} css - CSS string.
   * @returns {boolean} - True or false
   */
  private isSafeCss;
}
