Problem Solving & Design B

The app models the reading-pace problem cleanly, adds a useful deadline-tracking feature beyond the brief, and sorts the shelf by projected finish date so urgency is immediately visible.

• +An optional target date field computes whether the reader is on track, past deadline, or how many pages per day they need — a natural extension of the core scenario.
• +The shelf is automatically sorted so books finishing soonest appear first, making urgency visible without any user action.
• +The progress bar uses aria progressbar semantics with aria-valuenow, aria-valuemin, and aria-valuemax tied to real page values.
• -When pace is zero or omitted the finish date silently shows 'Set pace above 0.' inside the preview, but the card itself shows 'No pace' with no further guidance on what to enter.
• -The edit form inside a card does not expose a target-date field for books that were added without one, so readers cannot add a deadline after the fact — only update an existing one.

Completeness A

All brief-required features are implemented end to end, including live recalculation, multi-book shelf, card updates, removal, and localStorage persistence with seed data on first run.

• +Pages remaining, days to finish, and the human-readable finish sentence all update live as the user types, with no submit required.
• +Clicking a book card opens an inline edit form that lets the reader update their current page and pace, then saves back to the shelf.
• +The remove button asks for confirmation before clearing a book, preventing accidental deletion.
• +localStorage is written on every state change and read on startup, with seed books shown on first run.

Technical Craft B

The codebase is well-structured across focused modules with explicit TypeScript interfaces, thorough input validation, and consistent accessibility patterns, but has no automated tests.

• +Core logic — projection, deadline status, sorting, parsing, and validation — lives in pure named functions in a dedicated lib module, fully separate from React.
• +The store validates persisted data with a type-guard before using it, so corrupt localStorage entries fall back to seed data rather than crashing.
• +CSS custom properties define the full colour and radius system in one place, with a complete dark-mode override via prefers-color-scheme.
• -There are no automated tests anywhere in the repository; the pure functions in lib.ts are straightforward to unit-test but none exist.