Job Recruitment Website - Property management company - Help me look at the outline color of the decoration form. thank you

Help me look at the outline color of the decoration form. thank you

First, the FormBorderStyle of the form is set to None, so don't control the border.

TransparencyKey and BackColor are set to the same color, so the form is transparent.

On this basis, we can make transparent irregular shapes, set circular background pictures or draw them.

What needs to be solved is the event handling such as dragging \ closing a borderless form.