As a general rule of thumb, assume that people know basically nothing about technology beyond the general hand holding environment of, say, an iPhone or something like gmail
Every person whose posted quote unquote css crimes here should be required to teach a 60 year old who has figured out how the basic functions of a cell phone work but not much more how to use a word processor for at least an hour
I taught senior citizens how to call their grandkids over Skype a few years ago and I'm confident every single one of those people forgot everything I taught them the second they left the college campus that day