title: mkdocs: How to create Folder like structure
body: <p>I want to create a small local file with my personal lecture notes. The Structure that I want is </p>
  
  <p>Index 1 (contains overview of subfolders, but not the full content of them)
      Index 1.1 (contains overview of subfolders but not the full content of them)
          Index 1.1.1 (contains content of section)</p>
  
  <p>At the moment my mkdocs.yml looks like</p>
  
  <pre><code>site_name: Lectures
  
  theme: readthedocs
  
  extra_javascript: 
      - https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS-MML_HTMLorMML
  
  markdown_extensions:
      - mdx_math
  
  pages:
  - Lecture1 
    - 'week 1': 'lec1/week1.md'
        - 'section 1': 'lec1/week1/sec1.md
  </code></pre>
  
  <p>But the previous code does not display it like I want.</p>