What you are doing
Make it work on phones
Ask for responsive behaviour explicitly.
The three stacked lines that open a menu on a narrow screen.
WordDifficulty: beginner
Most of your visitors are on a phone. Say so, because it is not assumed.
GuideFills the constraint part
Treat this as a firm implementation constraint: mobile-first.
PatternFills the audience part
The main audience includes people visiting on a phone with limited time and attention. They are likely trying to find one fact or complete one task while away from a desk.
PatternA page that rearranges itself to stay usable on different screen sizes.
Word