After adding Zdoc theme for Hugo, I got the following warning message:
hugo server -D
WARN 2020/04/15 20:58:51 found no layout file for "HTML" for kind "taxonomyTerm": You should create a template file which matches Hugo Layouts Lookup Rules for this combination.
Solution
For the time being, I started learning Hugo and don't need the taxonomy feature. So, I simply disable it. I add disableKinds = ["taxonomyTerm"]
in ./config/_default/config.toml.