/// <summary> /// Adds a conditional nested CssBuilder to the builder with space separator. /// </summary> /// <param name="builder">CSS Class to conditionally add.</param> /// <param name="when">Condition in which the CSS Class is added.</param> /// <returns>CssBuilder</returns> public CssBuilder AddClass(CssBuilder builder, bool when = true) => when?AddClass(builder.Build()) : this;