They turn white for me (or green for sticky posts). However, there may be some combination of dark mode and theme setting that I’ve overlooked. The #app id should have the attribute data-bs-theme=“dark” if you use darkly. If your entire system use dark mode it should also work by default if your system tells your browser that you prefer dark themes. (But data-bs-theme will still be set to light unless one go to the settings and change the theme to darkly.)