Add opacity modifiers for color utilities

Author: adamwathan

__tests__/fixtures/tailwind-output-important.css

@@ -0,0 +1,45 @@
+import flattenColorPalette from '../src/util/flattenColorPalette'
+
+test('it flattens nested color objects', () => {
+  expect(
+    flattenColorPalette({
+      purple: 'purple',
+      white: {
+        25: 'rgba(255,255,255,.25)',
+        50: 'rgba(255,255,255,.5)',
+        75: 'rgba(255,255,255,.75)',
+        default: '#fff',
+      },
+      red: {
+        1: 'rgb(33,0,0)',
+        2: 'rgb(67,0,0)',
+        3: 'rgb(100,0,0)',
+      },
+      green: {
+        1: 'rgb(0,33,0)',
+        2: 'rgb(0,67,0)',
+        3: 'rgb(0,100,0)',
+      },
+      blue: {
+        1: 'rgb(0,0,33)',
+        2: 'rgb(0,0,67)',
+        3: 'rgb(0,0,100)',
+      },
+    })
+  ).toEqual({
+    purple: 'purple',
+    'white-25': 'rgba(255,255,255,.25)',
+    'white-50': 'rgba(255,255,255,.5)',
+    'white-75': 'rgba(255,255,255,.75)',
+    white: '#fff',
+    'red-1': 'rgb(33,0,0)',
+    'red-2': 'rgb(67,0,0)',
+    'red-3': 'rgb(100,0,0)',
+    'green-1': 'rgb(0,33,0)',
+    'green-2': 'rgb(0,67,0)',
+    'green-3': 'rgb(0,100,0)',
+    'blue-1': 'rgb(0,0,33)',
+    'blue-2': 'rgb(0,0,67)',
+    'blue-3': 'rgb(0,0,100)',
+  })
+})