Now in server version we use nested number lists such as
1. nested number lists
1.1. nested number lists
1.2. nested number lists
1.2.1. nested number lists
1.2.1.1. nested number lists.
This was done using "Add the following CSS code on Confluence space Stylesheet".
But for the cloud version this does not work, since access to the "Custom Stylesheet for Spaces" item is not active in the settings.

How to have nested number lists in Confluence Cloud?