Python: v3.10
Panel: v1.5.5
OS: macOS Sequoia 15.1.1
Browser: both Google Chrome and Firefox

Description

When using the dark theme, the active_header_background property is not being set for the Accordion component. It remains the default #ddd color defined here. This applies regardless of the design used - I tried material, bootstrap, and native; all of them had the same issue.

As a result of this issue, the Accordion background has an unreadable light color when opened, even though the different themes set the active_header_background property to a CSS variable (for instance, here).

Example code to reproduce

import panel as pn

pn.extension(theme="dark")

pn.Accordion(
    ("Test Accordion", pn.pane.Markdown("Test Content"))
).servable()

Browser inspect element

Screenshots

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