/**
 * A helper class for managing theme-related functionalities, such as setting the theme color in the meta tag.
 */
export declare class ThemeHelper {
    /**
     * Sets the meta theme color in the document's head. If the meta tag does not exist, it creates one.
     * This function can handle direct color values (e.g., hex, RGB, named colors) or CSS variables.
     * If a CSS variable is provided (e.g., 'var(--background)'), the method will resolve the actual color value
     * from the specified element in the DOM.
     *
     * @param color - The color to set for the theme, typically a string representing a hex code, RGB value, named color, or a CSS variable.
     *                If a CSS variable is used, it should be in the format 'var(--variable-name)'.
     * @param calculator_element - A CSS selector string that identifies the element from which the CSS variable's value should be computed.
     *                             This defaults to '#app .v-application'. If your CSS variable is defined in a different element,
     *                             provide the appropriate selector.
     */
    static SetMetaThemeColor(color: any, calculator_element?: string): Promise<void>;
    static SetHtmlFontSize(low_vision: boolean): void;
}