diff --git a/conf.py b/conf.py
index 7d175c4043..45d3d9f638 100644
--- a/conf.py
+++ b/conf.py
@@ -169,11 +169,14 @@
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-# html_static_path = ['_static']
+html_static_path = ['source/_static']
 
 # Drop any source link suffix
 html_sourcelink_suffix = ''
 
+# Relative to html_static_path
+html_css_files = ['custom.css']
+
 # -- Options for HTMLHelp output ------------------------------------------
 
 # Output file base name for HTML help builder.
diff --git a/source/_static/custom.css b/source/_static/custom.css
new file mode 100644
index 0000000000..4252f921bb
--- /dev/null
+++ b/source/_static/custom.css
@@ -0,0 +1,3 @@
+.wy-nav-content {
+    max-width: 64rem;
+}