Bookmarks bar GitHub icon not switching colors based on theme (day/night mode)

[hejiawei67]

Problem:
In the bookmark bar of Zen Browser, the manually added GitHub website icon (favicon) cannot automatically switch to a contrasting color version according to the system/browser theme (day/night mode) like Chrome browser. The current performance is:
Dark icon is displayed in day mode
Dark icon is still maintained in night mode
Insufficient contrast with the background makes it difficult to identify

How to automatically load the light version of the icon in night mode ? The icon color of the day/night mode should maintain sufficient contrast with the background to achieve the same adaptive switching logic as Chrome.