Adding knob on slider

Hi,

In my experiment, I have a section that uses sliders. I’m trying to customize their layout so that the knobs is displayed as a circle (white center with a black border) on each slider.

However, when I try to move the knob during the experiment, the white marker underneath the knob moves instead — the circle stays fixed in place.

Could anyone please let me know how to make the circular knob itself move with the slider value, rather than the underlying marker?

Here is a screenshot of the layout :

Idk if it will be relevent to mentioned, but I added a code component in the builder:

The JS code:

Thank you very much for your help.