To have Windows automatically pick an accent color, select Automatic. In the list for Choose your mode, select Light. You can play around with the colors and modes to see which ones work best for you.
This option is for the Start menu, taskbar, and action center. You can also show an accent color for window title bars (the horizontal bar at the top of a window) and borders. You can choose an accent color, or have Windows select one (the accent color will provide a contrast with, or match, your wallpaper and Windows color).
The Custom mode gives you options between Light and Dark. Note: The Light mode doesn't personalize the color of the Start menu, taskbar, and action center (that option is only available for Dark and Custom modes).
