Frontend & browser·Loading, assets and the critical path
the page stayed blank until a stylesheet in the head finished downloading from a third-party domain.
Render-blocking resource
Also calledblocking stylesheet, blocking script
A resource the browser will not paint without: any stylesheet in the document, and any synchronous script, which also blocks HTML parsing. Each one adds its full download time to first paint, and a chain of them adds up serially. The audit is short — count what is in the head, and for each one decide whether it is needed for the first screen or can be deferred.