Custom line-height values not applied via leading-* classes

[tylerbecks]

Describe the bug
Custom line-height values defined via CSS variables in the Tailwind theme are not being applied to React Native Text components when using NativeWind classes (e.g., leading-md, leading-lg). The fontSize and letterSpacing from the same theme configuration work correctly, but lineHeight is ignored.

Reproduction
https://github.com/tylerbecks/nativewind-line-height-issue

The reproduction includes side-by-side comparisons of the same text with identical typography values:

• One using NativeWind classes (text-md leading-md tracking-md)
• One using inline styles (style={{ fontSize: 17, lineHeight: 22, letterSpacing: -0.43 }})

Custom line-height values are defined in the theme using CSS variables and mapped to Tailwind classes via @theme inline.

Expected behavior
When applying className="text-md leading-md tracking-md" to a React Native Text component, all three properties (fontSize, lineHeight, letterSpacing) should be applied correctly, matching the values defined in the CSS variables.

Actual behavior

• ✅ text-md (fontSize) works correctly
• ✅ tracking-md (letterSpacing) works correctly
• ❌ leading-md (lineHeight) does NOT work - line-height is not applied

When the same lineHeight value is applied via inline styles, it works correctly, proving this is specific to NativeWind class application.

Additional context
Environment:

• NativeWind version: preview
• React Native version: 0.81.5
• Expo version: ^54.0.0
• Tailwind CSS version: ^4.1.13

[danstepanov]

@tylerbecks this is an incredibly detailed and well thought through issue, thanks, I'll take a look

[denizcdemirci]

I have a similar issue. Since line height doesn't work properly, none of the texts appear as intended, which causes the entire design to break. I'd really appreciate it if you could help.