parent selector in CSS is said to be included in new CSS draft as has() class. A stack overflow comment mentions about it.
Also, on this blog, the author says a reverse selector or parent selector is available with IE and WebKit-based browsers. Chrome was a WebKit-based until Google exited from the WebKit herd. However, in many document, Chrome is mentioned as WebKit-based and there are still lots of WebKit-ness there.
However, as of today, on my Chrome browser on Windows, this parent selector, <, is not available.The version of Chrome browser on my machine is Version 47.0.2526.106 m.
This single post contains lots of links for customizing a scrollbar.
StackOverFlow : CSS customized scroll bar in div
I happened to read some articles here at mobiForge.
It’s for mobile web app developers and articles are organized really well.
For example, “Starting”, “Designing”, “Developing”, “Testing” and “Running” are the main titles.
So, you can easily find articles for those each step.