Found while reviewing #1826. theme.css defines tint-* with an @prop at rule (line 42), but react-native-css renamed @prop to @nativeMapping in 3.0.0 and the compiler silently ignores @prop now. So -rn-tint never gets mapped to the tint prop and tint-* currently does nothing.

Fix is to switch theme.css to @nativeMapping and add a regression test asserting the value lands as a top level prop with an empty style, matching the @prop.tsx test conventions. The review on #1826 has the full analysis, that PR copied the same dead pattern.