> For the complete documentation index, see [llms.txt](https://www.oulan.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://www.oulan.com/2019/12/21.md). # 21 莫因负重而不跃 莫因身轻而忘飞 早安，世界。早安，未来。