<strong>
Strong importance, seriousness, or urgency.
Baseline: Widely available · Inline text semantics
When to use it
For warnings and key facts the reader must not miss; nesting increases importance.
When not to
Not for bold-as-style — attention without extra importance is b.
Example
Warning: the pan will be extremely hot.
<p><strong>Warning:</strong> the pan will be extremely hot.</p>