import { ComputedRef } from 'vue';
/**
 * Vue composable that returns the computed UI font-family for SuperDoc surfaces.
 *
 * This composable centralizes the logic for determining which font-family to use
 * across all SuperDoc UI components (toolbar, comments, dropdowns, tooltips, etc.).
 * It retrieves the configured font from the SuperDoc instance's config, validates it,
 * and falls back to the default if no valid font is configured.
 *
 * The font-family is determined by checking the `uiDisplayFallbackFont` config property.
 * If it's a non-empty string, it will be used. Otherwise, the DEFAULT_UI_FONT_FAMILY
 * constant is returned.
 */
export declare function useUiFontFamily(): {
    uiFontFamily: ComputedRef<string>;
};