ADDITIONAL SYSTEM INFORMATION :
Should be cross platform on all platforms that support dark mode

A DESCRIPTION OF THE PROBLEM :
Please add APIs to query the current system mode (light / dark), as well as to be notified when the system mode is changed at runtime.

SWT has https://help.eclipse.org/2019-09/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fapi%2Forg%2Feclipse%2Fswt%2Fwidgets%2FDisplay.html to query the mode, but nothing to get notified on changes. Major browsers (Chrome, Firefox, Safari) automatically switch their UI, as well as apply the right styling provided by the website when the system mode is changed by the user.

I've marked this for java.awt, since this looks like the right place. For example, Taskbar.setIconImage is one of such cross-platform APIs, guarded by the Taskbar.Feature.ICON_IMAGE