If anyone else was losing their mind from the chrome commonly used password alert that forcibly interrupts the demo just close and come back as user will already be logged in.
Chrome Developer Tools (F12) has this great tool called CSS Overview. It analyzes the colors on the page in various layers and gives some good information. Best thing for theme development is the Contrast Issues section as well as any other issue it reports from anything related to css.
Could have helped me here: https://imgur.com/a/mX7RGGh