Improve doc

Author: martaiborra

doc/conf.py

@@ -58,6 +58,7 @@
 # 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_css_files = [
     'css/custom.css',