Every web page you have opened is built from three layers, with HTML as the bones, CSS as the clothes and JavaScript as the movement. On this page you can switch each layer off and see what it was doing.
This card has a switch for each layer. With CSS off the styling disappears, and with JavaScript off the button stops answering.
One big block carries the main message, and smaller blocks fill the space around it.
Rows run from best at the top to worst at the bottom, and the colour of each row shows the ranking before you read a word.
The header says who the person is, and the grid underneath shows what they have made.
CSS can react to the mouse on its own. JavaScript is worth adding only when CSS cannot do the job.
The page remembers a number and shows it again each time it changes. Most apps do a great deal of exactly this.
One class added to one element changes every rule tied to that class at once.
A vague request gets a vague page back. Tell the AI what the page is for, what goes on it and how it should feel.
Here are three questions about the layers, and every answer comes with an explanation.