Chrome now supports dark scroll bar as Github has implemented. After careful search and debug I finally located 2 syntax for its implementation, being:

A HTML meta tag telling Chrome supported color-schemes with preference by order. Chrome users with system-wide light/dark theme will find it respect this tag on page reload. The light theme remains what it was, while the dark theme features a default pure black background and pure white font color, with other colors like purple for hyperlinks.

<meta name="color-scheme" content="light dark">

A CSS property which can override previous meta tag and works without reloading the page

:root {
  color-scheme: dark;
}

Reference

Improved dark mode default styling with the color-scheme CSS property and the corresponding meta tag