Tweak presentation of Colors guide.

Summary:
Explain a bit more how these are used.
Closes https://github.com/facebook/react-native/pull/12753

Differential Revision: D4663972

Pulled By: hramos

fbshipit-source-id: acbda6593e3f2a01776d2208f6ef3bc69bca0eef

docs/Colors.md

@@ -8,22 +8,37 @@ next: platform-specific-code
 previous: images
 ---
 
-The following formats are supported:
+Components in React Native are [styled using JavaScript](docs/styles.html). Color properties usually match how [CSS works on the web](https://developer.mozilla.org/en-US/docs/Web/CSS/color_value).
 
- - `'#f0f'` (#rgb)
- - `'#f0fc'` (#rgba)
- - `'#ff00ff'` (#rrggbb)
- - `'#ff00ff00'` (#rrggbbaa)
- - `'rgb(255, 255, 255)'`
- - `'rgba(255, 255, 255, 1.0)'`
- - `'hsl(360, 100%, 100%)'`
- - `'hsla(360, 100%, 100%, 1.0)'`
- - `'transparent'`
- - `'red'`
- - `0xff00ff00` (0xrrggbbaa)
+### Red-green-blue
 
+React Native supports `rgb()` and `rgba()` in both hexadecimal and functional notation:
 
-For the named colors, React Native follows the [CSS3 specification](http://www.w3.org/TR/css3-color/#svg-color):
+- `'#f0f'` (#rgb)
+- `'#ff00ff'` (#rrggbb)
+
+- `'rgb(255, 0, 255)'`
+- `'rgba(255, 255, 255, 1.0)'`
+
+- `'#f0ff'` (#rgba)
+- `'#ff00ff00'` (#rrggbbaa)
+
+### Hue-saturation-lightness
+
+`hsl()` and `hsla()` is supported in functional notation:
+
+- `'hsl(360, 100%, 100%)'`
+- `'hsla(360, 100%, 100%, 1.0)'`
+
+### `transparent`
+
+This is a shortcut for `rgba(0,0,0,0)`:
+
+- `'transparent'`
+
+### Named colors
+
+You can also use color names as values. React Native follows the [CSS3 specification](http://www.w3.org/TR/css3-color/#svg-color):
 
 - <color aliceblue /> aliceblue (#f0f8ff)
 - <color antiquewhite /> antiquewhite (#faebd7)

docs/Style.md

@@ -8,7 +8,7 @@ next: height-and-width
 previous: state
 ---
 
-With React Native, you don't use a special language or syntax for  defining styles. You just style your application using JavaScript. All of the core components accept a prop named `style`. The style names and values usually match how CSS works on the web, except names are written using camel casing, e.g `backgroundColor` rather than `background-color`.
+With React Native, you don't use a special language or syntax for  defining styles. You just style your application using JavaScript. All of the core components accept a prop named `style`. The style names and [values](docs/colors.html) usually match how CSS works on the web, except names are written using camel casing, e.g `backgroundColor` rather than `background-color`.
 
 The `style` prop can be a plain old JavaScript object. That's the simplest and what we usually use for example code. You can also pass an array of styles - the last style in the array has precedence, so you can use this to inherit styles.