<style>
Embeds CSS directly in the document head.
Baseline: Widely available · Document structure
When to use it
For small critical CSS inlined for performance, or single-file self-contained documents.
When not to
For anything beyond trivial size, an external stylesheet caches independently of the HTML; and never use style as a substitute for semantic element choice.
Key attributes
media- conditional media query
Example
<style>
body { max-inline-size: 65ch; margin-inline: auto; }
</style>