Zero code is in your head if you can't read it.<p>The predominant monitor in existence is your average 24" 1080p monitor, sat at, on average, 32" away from the head. The average person has worse than 20/20 vision.<p>You must test your website in such conditions and make sure it is readable, and also make sure it meets at minimum WCAG A, but preferably the whole way to AAA if possible.
The predominant monitor's probably a smartphone. The average professional is using a 4k monitor.<p>Everything in the free documentation I've provided you out of my own time and money that you're referring to exists in relation to the other elements in that page, so to get the experience you're after simply ctrl+scroll and change the CSS zoom level like the riot at parties that you could be or catch up with circa 2013-2014 and invest in a 4k display.