CSS style for Slider CFF

Hi, please help me with setting up the slider slider. I studied the help information https://cff.dwbooster.com/faq#q82, looked for a similar question, nothing helped.

You need to style the CFF slider this way: https://codepen.io/spacemakerman/pen/BaMQxBm
What needs to be done for this?
I only managed to change the line thickness and color, but how to change thumb ?