Reproduce navigation overflow with long and translated labels, repair nested flex and text constraints, and verify reflow and keyboard access.
Test visible keyboard focus on a link, input and working button, and distinguish focus-visible from hover and pointer focus.
Build a complete main-and-sidebar layout, reproduce long-content overflow, and verify track widths, the mobile breakpoint and keyboard access.
Choose a breakpoint by testing real card content, compare 719px with 720px and distinguish CSS viewport width from device resolution.
Anchor badges to separate cards, inspect their containing block and distinguish a visual relative offset from normal-flow spacing.
Compare natural sizing, cover and contain with one downloadable test image. Measure the result and choose cropping deliberately without stretching the artwork.
Reproduce an anchor hidden beneath a sticky header and keep a measured scroll offset correct when the header wraps.
Build and test a local email validation flow that explains errors, preserves the typed value and clears stale error states after correction.
Migrate a button to shared brand tokens, override one section, and check hover, keyboard focus and fallback behaviour in a complete local example.
Replace a data-or-error object with a union tagged by success, then add a generic Outcome and an unwrap helper. After this, the compiler knows which property exists in each case.
Compare import type, the inline type keyword and a plain import, and see which ones leave code in the compiled file. After this, a types-only import cannot load a module with side effects.
Read a long assignability error from the bottom, then fix the usual causes: a wrong value, a wrong type and a literal widened to string. After this, a nested mismatch points to one property.