Users who want to override specific theme stylings can do so by injecting a custom stylesheet into the generated output. For example, a user can create a stylesheet _static/theme_overrides.css with the following options added into conf.py:

html_context = {
    'css_files': ['_static/theme_overrides.css'],
html_static_path = ['_static']

Example styling of a user overriding the header color is as follows:

h1 {
    color: #ff0000 !important;