public virtual async Task <IActionResult> SetStoreTheme(string themeName, string returnUrl = "")
        {
            await _themeContext.SetWorkingThemeNameAsync(themeName);

            //home page
            if (string.IsNullOrEmpty(returnUrl))
            {
                returnUrl = Url.RouteUrl("Homepage");
            }

            //prevent open redirection attack
            if (!Url.IsLocalUrl(returnUrl))
            {
                returnUrl = Url.RouteUrl("Homepage");
            }

            return(Redirect(returnUrl));
        }