can not export pdf for page which contains cjk characters

here is the error

```
An error occured: PDF creation failed:
! Package inputenc Error: Unicode char 以 (U+4EE5)
(inputenc) not set up for use with LaTeX.

See the inputenc package documentation for explanation.
Type H for immediate help.
...

l.62 以

Try running pandoc with --latex-engine=xelatex.
```