HumanUI Expander border color

HumanUI Expander border (11.0 KB)

How can I change the color of the border in an Expander?
It is easy to change the header color but I can’t modify the color of the border.

Check this post, it has the answer:

You need to change the Accent color in the window properties. This will change the color to all your slider bars, frames, etc. So it becomes the theme color of your window.
Unfortunately you can’t have much control, only being able to use a specific range of colors.
You can copy from the file I attached.
Human UI Accent color
Human UI_Accent (6.0 KB)