Description
areHintedStyles() expects ["h1", "h2", "h3", "h4", "h5", "h6", "caption", "body"] and uses .every() to check if additionalStyles.Text is a hinted styles object.
This requires all 8 keys including h6 to be present. In practice, themes rarely define h6 styles (the HintedStyles interface doesn't even declare it). When any key is missing, the check returns false and the entire object is passed to styleMap() as a flat Record<string, string> — but the values are nested objects, so nothing gets applied.
Location
lit/src/0.8/ui/text.ts [Line 125 - 132]
Suggested fix
Change .every() to .some() and remove h6 from the expected list so any recognized key triggers hinted mode