Page customization using less, sass, and scss, is currently unavailable.
Incident Report for Atlassian Statuspage
This incident has been resolved.
Posted Jan 13, 2021 - 16:37 PST
We are currently investigating an issue preventing users from being unable to edit a page's custom CSS if using less, sass, or scss.

Standard CSS use is not impacted.
Posted Jan 11, 2021 - 15:37 PST
This incident affected: Management (Web Portal).