Our stretch target is a 100 PageSpeed score on merchant storefronts. A score is not a guarantee—it varies by page, data, device, network, and Lighthouse version—but the target forces us to keep the render path small.

The Problem With One Big CSS File

A render-blocking styles.css can delay the first paint while the browser downloads, parses, and applies the rules needed for the page. For a marketplace with catalog pages, account dashboards, rich text editors, and storefronts, one shared file can grow quickly.

Our Three-Tier CSS Strategy

We split CSS into three categories based on when it's needed:

1.…