Document theme change

Need to change ru and pt as well

doc/manual-src/en/_static/default2.css

@@ -7,3 +7,9 @@ pre, tt {
 tt {
     font-size: 100%;
 }
+
+div.body h1, div.body h2, div.body h3, div.body h4, div.body h5, div.body h6 {
+    border: 0;
+    margin: 0;
+    padding: 0.3em 0;
+}

doc/manual-src/en/conf.py.in

@@ -97,7 +97,16 @@ html_theme = 'default'
 # further.  For a list of options available for each theme, see the
 # documentation.
 html_theme_options = {'bodyfont':'roboto, sans-serif',
-                      'headfont':'roboto, "Trebuchet MS", sans-serif'}
+                      'headfont':'roboto, "Trebuchet MS", sans-serif',
+                      'relbarbgcolor':'#fff',
+                      'relbartextcolor':'#444',
+                      'relbarlinkcolor':'#444',
+                      'sidebarbgcolor':'none',
+                      'sidebartextcolor':'#444',
+                      'sidebarlinkcolor':'#444',
+                      'headbgcolor':'none',
+                      'footerbgcolor':'none',
+                      'footertextcolor':'#444'}
 
 # Add any paths that contain custom themes here, relative to this directory.
 #html_theme_path = []