How to streamline SASS/CSS

• Tried changing font-size of the webpage from 14px to 16px, but it doesn't show any changes!
• It's seen than It's not clear which files and/or attributes control site characteristics.
• How to streamline the SASS/CSS for this website to give a straightforwardness, easily discoverable SASS for the website and its various areas.

Webpage: https://deploy-preview-12368--kubernetes-io-master-staging.netlify.com/docs/home/

Source code: https://github.com/kubernetes/website/

Pull request given: https://github.com/kubernetes/website/pull/12368

File changes: https://github.com/kubernetes/website/pull/12368/files