阅读下列短文，根据短文内容填空，在未给提示词的空白处仅填写1个适当的单词，在给出提示词的空白处用括号内所给词的正确形式填空。

Why is the Forbidden City called "purple forbidden city"? If you have visited it, you may find that the palace (paint) mainly in two colors, yellow and red.  Red, the color of fire, shows happiness and (succeed), while yellow, the color of the sun, was only used by the emperors, who were regarded as the Sons of Heaven. Ancient Chinese astronomers believed that Polaris (北极星), "Ziwei star", was in the center of heaven and the heavenly emperor lived in the Ziwei Palace. So the palace for the emperor on Earth should be like the one in heaven. That is "purple" is in the name.