How to markdown nested list items in Bitbucket?

I’m trying to see my markdown nested list items rendered with corresponding indentation when viewed in a browser live from the Bitbucket pages. But I can’t figure out how it works even when using their examples (updated):

* Item 1
* Item 2
* Item 3
  * Item 3a
  * Item 3b
  * Item 3c

It ignores indentation for items 3a-c:

I want it to look like this (syntax works perfectly fine on SE and Github):

Their list in list example is particularly unacceptable:

1. Step 1
2. Step 2
3. Step 3
   * Item 3a
   * Item 3b
   * Item 3c

Here’s a repo I set up just for this.