title: How to add custom css file to Sphinx?
body: <p>How can I add a custom css file? The following config does not work:</p>
  <pre><code># conf.py
  html_static_path = ['_static']
  html_theme = 'default'
  html_theme_options = {
    'cssfiles': ['_static/style.css']
  }
  </code></pre>
  <p>Result:</p>
  <pre><code>C:\temp\test-docs\docs&gt;make html
  Running Sphinx v1.2.2
  loading pickled environment... not yet created
  building [html]: targets for 2 source files that are out of date
  updating environment: 2 added, 0 changed, 0 removed
  reading sources... [ 50%] help
  reading sources... [100%] index
  
  looking for now-outdated files... none found
  pickling environment... done
  checking consistency... done
  preparing documents...
  Theme error:
  unsupported theme option 'cssfiles' given
  </code></pre>