Foundation

Responsive meaning

What changes at sm/md/lg

RequiredInteraction & accessibility
ContractResponsive meaning
Job
What changes at sm/md/lg
Requirement
must specify
States / rules
Project declares mobile-first vs responsive vs adaptive; per component: reflow, collapse, or hide — never “it’ll scale”
Specified means
Per-component behavior written
Hardest context
Overlay + shell at 375
Example

List stacks; editor density drops

Counter-example

Desktop screenshot only

Shared guidance

Building Blocks role

Building Blocks can provide semantic guidance, examples, and reusable hooks.

Product obligation

The product still maps roles to its own theme and documents exceptions.

How this lives in Building Blocks

Representation: Shared guidance + product-local policy.

Building Blocks should provide shared guidance, semantic roles, examples, and reusable implementation hooks where appropriate. Each product maps those roles to its own theme and documents any justified exceptions.

Write what changes, not “responsive.”

Reflow

Content keeps meaning while order/layout changes.

Collapse

Chrome condenses into an explicit alternative such as a drawer or disclosure.

Hide

Only secondary information may disappear, and the product must justify it.

Density

Touch targets and reading order survive a tighter layout.

Continuity

State, focus, and navigation origin survive transitions between contexts.

Exercise these contexts
  • Overlay + shell at 375
  • Long content at 200% zoom
  • Keyboard navigation after a rail becomes an overlay

Do not specify the easy case only.

The source checklist’s hardest-context test is part of what “specified” means: Overlay + shell at 375.

On-spec signal

List stacks; editor density drops

Failure signal

Desktop screenshot only

Catalog connection

The product-local Catalog should show this row’s actual state for that product using the Catalog contract. Building Blocks documentation can define the baseline, but it does not make a product’s row Specified, Designed, or In code by itself.

See the Catalog contract →