In macOS Tahoe, Apple introduces the concept of Themes, with new appearance settings that go beyond the traditional Light and Dark modes, allowing you to customize the look of your Mac desktop more than ever. Here’s what’s changed.
In System Settings ➝ Appearance, there are still the standard Auto, Light, and Dark modes, but Apple has added several options that allow you to really mix things up and create your own stylized desktop environment.
“Accent color” has become “Color,” and there’s a new “Text highlight color” option, so you can now make highlighted text appear in a different shade to buttons, pop‑up menus, radio buttons, checkboxes, and focused outlines.
Read more at MacRumors.com