Step 3 — Principal Engineer Review

1. An engineer proposes replacing flexbox with absolute positioning in a hot list "for performance". You have the measurement. Write the review comment, including what they may be right about.

2. Your design system's <Card> takes a size="compact" | "comfortable" prop that consumers set based on where they are placing it. Container queries now exist. Should the prop go? Give the migration path and the case for keeping it.

3. A team reports "adding container-type broke our layout — the wrapper collapsed." Diagnose it without seeing the code, and give the two possible fixes.

4. Where should container-type live in a design-system component: the component root, a wrapper the component renders, or the consumer's element? Argue each, then decide.

5. Your CLS is 0.28. Enumerate the likely causes in order of probability, and say which are layout decisions versus loading decisions.

6. A component uses cqw units. A consumer forgets container-type. What happens, why is it hard to notice, and how would you make the failure loud?

7. Phase 1 has now produced three measured folklore corrections (fe-03 delete vs property order; fe-04 div soup size; fe-06 layout modes). Design the team practice that catches this class of error before it becomes a standard. What does it cost, and what stops it becoming bureaucratic?

8. When is a fixed pixel dimension the correct choice over fit-content? Give two cases and what you must pair them with.

9. subgrid would solve an alignment problem cleanly but you must support a browser without it. Give three strategies with different failure modes, and say which you would ship.

10. Argue against this module's conclusion. Construct a realistic scenario in which layout mode choice is the dominant cost, and say how you would recognise it from a profile.

Answers in RESULTS.md. Questions 2, 4 and 7 are natural ADRs.