Chrome now supports dark scroll bar as Github has implemented. After careful search and debug I finally located 2 syntax for its implementation, being:
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">
CSS property which can override previous
meta tag and works without reloading the page