Error 500 is a clean, responsive and free WordPress theme. It is developed as a Quark child theme.
You can see all the features on this link.
You can see a demo on this link.
If you want to know how to install it you have information on this link.
Error 500 is available for download on GitHub, with GNU/GPL v2 license.
And if you want to see it in action, you can go to:
- Error 500, Antonio Ortiz’s blog.
- Jesús Amieiro’s blog.