The book instructs readers to:

Open up lib/pento_web/live/product_live/index.html.heex and add a header that renders the value of the @greeting assignment.​ 

<h1 class=​"text-2xl font-bold"​><​%=​ ​@​greeting ​%​></h1>”

This might just be a me problem, but since it said “add a header” I just kind of unthinkingly put it inside the <.header> component - because at that point in the book I don’t really know what <.header> is.

Since it was then effectively rendering an H1 inside an H1, it resulted in some busted markup. That led me down a whole rabbit hole during which I wondered if Phoenix components themselves were busted and the framework wasn’t so stable after all!

Again - maybe it’s just a me thing, and take it or leave it, but my suggestion would be to change the language to say something more like “add a header that renders the value of the @greeting assignment to the very top of the file.”