Confluence not loading CSS properly on user interface after upgrade

[Hieu Nguyen]

Hi everyone,

I’ve just upgraded Confluence from version 8.9.8 to 9.2.4, and I’m encountering an issue where the user interface is not loading CSS properly, resulting in layout and color display problems.

Issue details:

• The main user interface doesn’t render the header styling correctly — the background color and text color are missing.

• When inspecting with DevTools, I see that the following CSS variables are not being applied properly:

  #header .aui-header {
  background-color: var(--confluence-color-scheme-topBarColor, var(--ds-surface));
  color: var(--confluence-color-scheme-breadcrumbsTextColor, var(--ds-text-subtle));
  }

• As a result, the header text is hard to read or invisible due to missing background and text colors.

• However, the admin interface loads CSS and displays correctly. The issue only happens on the regular UI.

What I’ve tried so far:

• Cleared browser cache

• Deleted Confluence cache directories (<confluence-home>/temp, work, etc.)

• Restarted the Confluence service

None of these resolved the issue.

System details:

• Current version: Confluence 9.2.4

• Previous version: 8.9.8 (no issues)

• OS: Windows Server

• Browser: Chrome, Firefox (same behavior)

• Deployment: Running as a Windows service

---

Questions:

• Has anyone experienced this issue with CSS variables (e.g. --ds-surface, --ds-text-subtle) not being applied after upgrading?

• Could this be related to caching, theme changes in Confluence 9, or permission issues?

• Is there a way to force Confluence to reload or reset these CSS variables?

Thanks in advance for any help or suggestions!

[Hieu Nguyen · Accepted solution]

After discussing the issue with Atlassian Support, I received their assistance and was able to resolve the problem.

It turned out that the issue was caused by a customization we had made in the Main Layout.

I followed your instructions and reverted the Main Layout in the Look and Feel section, and it worked perfectly!

[Piyush Annadate _ACE Pune_]

Hello @Hieu Nguyen 
Welcome to the community !
Have you tried other browsers - is that same?
As you behind any proxy or so?

I would suggest to check with Atlassian Support to investigate the actual library loading issue based on logs . 

Support.atlassian.com 

[Hieu Nguyen]

Hi MR @Piyush Annadate _ACE Pune_ ,

Thank you for your response!

I’ve already tried using Chrome, Firefox, and Edge, and also tested on multiple different computers — the issue still persists.

As I mentioned earlier, the admin pages load normally. The problem only occurs on the user-facing pages. So I don't think the problem is related to the proxy

Thanks again!