How to customize scroll ruler

### Issue type
* [ ] bug report
* [x] feature request
* [ ] question about the decisions made in the repository

### Issue description

**Current behavior:**

I didn't found any information how to customize a scroll ruler.

**Expected behavior:**

Right now it's almost invisible and too thin on corporate theme

**Steps to reproduce:**

When you open page with a lot data you need to scroll sometimes and scrolling through ruler sometimes more convenient. But the ruler is too thin.