Jekyll Styleguide

Installation

# Install Jekyll and Bundler gems through RubyGems 
~ $ gem install jekyll
 
# Build the styleguide on the preview server 
~ $ jekyll serve

Fill the properties inside _config.yml:

# Styleguide specific 
styleguide-css: ""  # (opt) your styleguide stylesheet url 
styleguide-js: ""   # (opt) your styleguide javascript url

or place your styleguide stylesheet inside the /dist folder (names should be the same):

dist
├── css
│   └── styleguide.css
└── js
    └── styleguide.js

I don't like the styleguide/ path in my browser url, can I change it to dog/?

Change your _config.yml collection to:

collections:
  styleguide:
    output: true
    permalink: dog/:path/

I want more than two-level secondary menu, is it possible ?

Not yet sadly.