base_path.html

{% comment %}
This is adapted from: https://ricostacruz.com/til/relative-paths-in-jekyll

`page.url` gives the URL of the current page with a leading /:

- when the URL ends with the extension (e.g., /foo/bar.html) then we can get
  the depth by counting the number of / and remove - 1
- when the URL ends with a / (e.g. /foo/bar/) then the number / gives the depth
  directly
{% endcomment %}

{% assign relative_root_path = '' %}

{% assign last_char = page.url | slice: -1 %}

{% if last_char == "/"}
{% assign offset = 0 %}
{% else %}
{% assign offset = 1 %}
{% endif %}

{% assign depth = page.url | split: '/' | size | minus: offset %}
{% if    depth <= 1 %}{% assign relative_root_path = '.' %}
{% elsif depth == 2 %}{% assign relative_root_path = '..' %}
{% elsif depth == 3 %}{% assign relative_root_path = '../..' %}
{% elsif depth == 4 %}{% assign relative_root_path = '../../..' %}
{% endif %}