Here's a little exercise suggested by Virginia DeBolt.

Using the Gilder/Levin method on page 65 of CSS Mastery we hide text under an image. The images would typically be a heading image but I've used Clyde and his eyes.

Now expand the size of the text on the page in your browser by typing Ctrl + (Command +) or however you do it in your setup, repeatedly, and see what happens.

Hello World I am Clyde

I see you