export declare function findUpUntil(node: HTMLElement, callback: (element: HTMLElement) => boolean): HTMLElement | null;
export declare function supportsStickyPosition(): boolean;
export declare function getContainingBlock(startElement: HTMLElement): HTMLElement | null;
export declare function parseCssVariable(value: string): string;
export declare function nodeContains(parent: Node | null, descendant: Node | null): boolean;