/**
* Scope a CSS string, adding a compnent-specific trailing selector to all rules.
* It also converts `:host` selectors for cross browser compatibility.
* @param name The component definition name.
* @param cssText The CSS string.
* @returns A scoped CSS string.
* @throws If the scope name is not a string.
* @throws If the CSS value is not a string.
*/
export declare const css: (name: string, cssText: string) => string;