code: protected Declaration createDeclaration(String property, Term<?> term)
      {
          Declaration d = CSSFactory.getRuleFactory().createDeclaration();
          d.unlock();
          d.setProperty(property);
          d.add(term);
          return d;
      }
docs: Creates a single property declaration.
  @param property Property name.
  @param term Property value.
  @return The resulting declaration.