This PR moves support for opacity modifies from the CSS `theme()`
function into the plugin `theme()` implementation, this will allow
plugins to use this, too:
```ts
let plugin = plugin(function ({ addUtilities, theme }) {
addUtilities({
'.percentage': {
color: theme('colors.red.500 / 50%'),
},
'.fraction': {
color: theme('colors.red.500 / 0.5'),
},
'.variable': {
color: theme('colors.red.500 / var(--opacity)'),
},
})
})
}
```
There's a small behavioral change for the CSS `theme()` function. Since
tuples are resolved by default for the CSS `theme()` function only,
these will no longer have opacity applied to their first values. This is
probably fine given the reduced complexity as I don't expect the first
values of tuples to be colors and the fix would mean we would have to
parse the modifier in different places.
8f8803d855