Customize sphinxdoc theme

All I wanted is to add ReST strikethrough in my sphinx doc. Here is how I did it:

$ cd my-sphinx-dir
$ mkdir -p theme/static
$ touch theme/theme.conf
$ touch theme/static/style.css

In theme/theme.conf:

[theme]
inherit = default
stylesheet = style.css
pygments_style = pygments.css

(this makes it look like the default theme (l. 2))

In theme/static/style.css:

@import url("default.css"); /* make sure to sync this with the base theme's css filename */

.strike {
    text-decoration: line-through;
}

Then, in your conf.py:

html_theme="theme" # use the theme in subdir 'theme'
html_theme_path = ['.'] # make sphinx search for themes in current dir

(Optional) In global.rst:

.. role:: strike
   :class: strike

and in a example.rst:

.. include:: global.rst

:strike:`This looks like it is outdated.`