Problem Solving & Design 48

The app covers the brief's required outputs with clear stat cards and a fuel-level chart, but interactive elements lack hover/focus visual feedback and there are no ARIA attributes to support assistive technology.

• +The tank-level gauge changes colour at low fill levels, giving an immediate visual warning when the starting fuel is critically low.
• +The fuel-level chart plots vertical jumps at each refuel point alongside the gradual drain segments, making the trip's fuel profile easy to read at a glance.
• +Form controls use explicit label elements with matching for/id pairs, giving most inputs an accessible name.
• -No hover, focus, or active styles are defined for the number inputs, range sliders, or the unit toggle, so keyboard and pointer users get no visual feedback on interactive elements.
• -No ARIA roles, live regions, or aria-label attributes are present anywhere in the markup, so screen readers receive no announcement when results update after input changes.

Completeness 54

All core brief features are present and functional in a single self-contained file, with live recalculation, unit toggling, a road SVG, a fuel-level chart, and a stop schedule list.

• +The unit toggle converts existing input values between imperial and metric rather than resetting them, preserving the user's context across the switch.
• +A safety reserve of 10% is baked into the stop-spacing algorithm, so stops are planned before the tank actually empties.
• +The stop schedule list shows each stop's cumulative distance, leg distance, and refuel amount, giving the driver actionable detail.
• -All logic — calculation, DOM binding, SVG drawing, and unit conversion — lives in one flat script block with no module boundaries, making the code hard to maintain or extend.
• -When inputs are invalid the warning box is shown but outputs are set to "--" with no further guidance; there is no path that surfaces a recovery suggestion to the user.
• -There are no loading or pending states; while all calculations are synchronous here, the pattern is absent and would be needed if any async work were added.

Technical Craft 27

The implementation is a clean single-file SPA with a consistent design token system and smooth transitions, but it has no type definitions, no automated tests, and core logic is written inline rather than in named, testable functions.

• +Design tokens for colours, backgrounds, and borders are declared once in :root and referenced throughout, forming a consistent visual system.
• +The unit-toggle slider uses a cubic-bezier transition, adding intentional motion to the mode switch.
• -There are no explicit type definitions, interfaces, or JSDoc annotations anywhere; all function signatures and data shapes are implicit, making the code harder to verify or refactor safely.
• -The core trip calculation is written as a single while-loop inside calc() rather than extracted into a named, independently testable function.