Do external stylesheets get loaded before the HTML?

Style sheets don't prevent the document from being downloaded, but the browser won't render the document until all of the linked stylesheets have been downloaded and loaded into the DOM.

This is so that the browser doesn't need to render the page twice (wasting time in the process), and so that an unstyled page won't flash in front of the user before the stylesheets have been downloaded and parsed.

If you include the CSS in the head section, you can be confident that the label will not show.

The HTML is downloaded first. The browser starts reading the html from the top, and starts fetching all CSS and JavaScript files referenced in the HEAD section. The page will not be painted (shown) until all the CSS and JavaScript files in the HEAD have been downloaded and evaluated.