rtd theme adjustment: borg darkness for the upper left corner

docs/borg_theme/css/borg.css

@@ -0,0 +1,18 @@
+@import url("theme.css");
+
+/*  The Return of the Borg.
+ *
+ *  Have a bit green and grey and darkness (and if only in the upper left corner).
+ */
+
+.wy-side-nav-search {
+    background-color: black;
+}
+
+.wy-side-nav-search > a {
+    color: rgba(255, 255, 255, 0.5);
+}
+
+.wy-side-nav-search > div.version {
+    color: rgba(255, 255, 255, 0.5);
+}

docs/conf.py

@@ -127,7 +127,8 @@ html_favicon = '_static/favicon.ico'
 # 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 = ['borg_theme']
+html_style = 'css/borg.css'
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page bottom,
 # using the given strftime format.