You can fully customize the look and feel of your desktop using this comprehensive guide, and you can use these steps to optimize the taskbar space on Windows 10. Once you complete the steps, surfaces like the Start menu, action center, and the taskbar will now show the accent color you selected in the Colors settings page. Under the 'Show accent color on the following surfaces' section, you can now check the Start, taskbar, and action center option. Ask VG discovered a Registry key that handles the inactive titlebar color. Windows 10 users who want to change the color of inactive titlebars in the operating system had to resort to third-party solutions until now. Quick tip: If you're using the Custom option, make sure you select the Dark option for 'Windows mode.' The screenshot below highlights how that looks currently if you have set a different color for the active titlebar in Windows 10. Use the 'Choose your color' drop-down menu and select the Dark or Custom option.

To make the accent color option for Start, taskbar, and action center available on Windows 10, use these steps: How to fix accent color for Start, taskbar, action center

Windows 10 inactive title bar color