`org-html-export-to-html` not adding color for the code blocks

Question

I have an org file with the following code block:

#+begin_src emacs-lisp
(+ 1 2)
#+end_src

And when I export it using M-x org-html-export-to-html, the code blocks in the generated file have no color.

They have a src and a src-emacs-lisp CSS classes, but the only thing inside the file is:

pre.src-emacs-lisp:before { content: 'Emacs Lisp'; }

I have org-src-fontify-natively set to t, and I tried using both css and inline-css as values for org-html-htmlize-output-type, but nothing fixed it.

I remember exporting as HTML some months ago in a different machine, and the code blocks had color.

Answer 1

Install htmlize package with M-x package-install RET htmlize RET.

Org export uses htmlize to highlight code blocks in html.