目的

sphinx_rtd_themeの横幅を広げる（など）
property属性が１行に詰め込まれてレイアウトされるのを防ぐ

仕掛け

docs/source/_static/css/custom_sphinx_rtd_theme.css

/*
 * 「Sphinx の sphinx_rtd_theme をカスタマイズする」
 * https://kuttsun.blogspot.com/2016/11/sphinx-sphinxrtdtheme.html
 */

.wy-nav-content {
    max-width: 1600px;
}

h1,h2,h3,h4,h5,h6 {
    border-bottom: 1px solid #ccc;
}

.wy-table-responsive table td, .wy-table-responsive table th {
    white-space: normal;
}

colgroup {
    display: none;
}

docs/source/_static/css/fix-layout-pyproperty.css

/*
 * py:property's stacking on a single line on larger screen widths.
 * https://github.com/readthedocs/sphinx_rtd_theme/issues/1301
 *
 * > Problem
 * > Multiple properties I defined in the docs are all stacking on a single line.
 * > （ドキュメントで定義した複数のプロパティがすべて1行に重なっている）
 *
 * https://github.com/readthedocs/sphinx_rtd_theme/issues/1301#issuecomment-1219961515
 * https://gist.github.com/nocarryr/846301fd5c9083e2243346d19e55b5a3#file-override-css
 */

dl.py.property {
    display: block !important;
}

sphinx-apidoc -Fコマンドで生成されるconf.pyに以下を設定

docs/source/conf.py

# -- Options for HTML output -------------------------------------------------
# https://www.sphinx-doc.org/en/master/usage/configuration.html#options-for-html-output

html_theme = 'sphinx_rtd_theme'
html_static_path = ['_static']
html_css_files = ['css/custom_sphinx_rtd_theme.css', 'css/fix-layout-pyproperty.css']

参考URL

Sphinx の sphinx_rtd_theme をカスタマイズする
py:property's stacking on a single line on larger screen widths.