-ms-grid stylesheet vs JavaScript polyfill for IE10 Grid support in low‑traffic internal apps

For an internal tool that must run on IE10, the team needs to decide how to provide CSS Grid layouts while keeping overall effort low.

The options are to author a separate stylesheet using IE10’s prefixed -ms-grid properties or to load a JavaScript polyfill that translates modern display: grid syntax to the prefixed engine.

The prefixed approach avoids runtime overhead but requires explicit row/column placement for each child and lacks auto‑placement, gap, fr units and grid-template-areas, increasing authoring complexity.

The polyfill adds ~30 KB gzipped and triggers layout recalculations on IE10’s Chakra engine, which may affect frame timing on complex grids.

Given the low traffic volume, the team wants to understand which option yields the lower combined cost of authoring time and runtime performance.

Does the polyfill’s layout recalculation time exceed the authoring time saved by using modern grid syntax?
What is the measurable impact on page load time in IE10 when the polyfill is active for a typical internal dashboard?
Is maintaining a separate -ms‑grid stylesheet feasible given the lack of grid‑template‑areas and fr units?