Using universal border-box sizing. Every element will inherit the box-sizing from their parent. In case third-party components will have box-sizing: content-box, using the inherit keyword will make the conversion easier.
CSS flexbox layout
svg – use
The <use> element takes nodes from within the SVG document, and duplicates them somewhere else. Resources MDN
Get style rules from stylesheet
Look into CSS style rules of this site.
Detect window scrollbars-demo
Has a vertical ScrollBar Has a horizontal ScrollBar