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--- a/README.md
+++ b/README.md
@@ -1,12 +1,67 @@
+# Memo
+Target reader: Engineer who developing mobile app.
+Purpose of this description: Make them want to use this library.
+Style: Fan & casual technical document. To make engineers feels easy.
+
+----
+
 # Colorful
 
+Colorful is intuitive color picker library written in Swift.
+It is designed easy to use for you and your app users.
+
 [![CI Status](https://img.shields.io/travis/hayashi311/Colorful.svg?style=flat)](https://travis-ci.org/hayashi311/Colorful)
 [![Version](https://img.shields.io/cocoapods/v/Colorful.svg?style=flat)](https://cocoapods.org/pods/Colorful)
 [![License](https://img.shields.io/cocoapods/l/Colorful.svg?style=flat)](https://cocoapods.org/pods/Colorful)
 [![Platform](https://img.shields.io/cocoapods/p/Colorful.svg?style=flat)](https://cocoapods.org/pods/Colorful)
 
+## Reason why you choose colorful
+
+### Intuitive UI.
+
+It's include hue-saturation wheel and brightness slider.
+UI interact quickly with perfect small animation and **haptic feedback**.
+
+![](https://github.com/hayashi311/Color-Picker-for-iOS/raw/screenshot/ColorfulUI.gif)
+
+### Wide color space support
+
+Wide color space is supported from iOS10.
+Now, `UIColor.red` is not "reddest" red any more.
+
+```
+// before iOS10
+let red = UIColor.red // reddest
+
+// Now
+let red = UIColor(displayP3Red: 1, green: 0, blue: 0)
+```
+
+Extended sRGB Color Space is designed to support wide color space with keeping compatible from sRGB.
+
+You can choose both color spaces with Colorful. 
+Extended sRGB for choosing brilliant color, sRGB for compatible.
+
+| Color Space |  |
+| :-------: | :---------: |
+| .extendedSRGB | Brilliant color |
+| .sRGB | Compatibility |
+
+![](https://github.com/hayashi311/Color-Picker-for-iOS/raw/screenshot/ColorPicker_ColorSpace.png)
+
+### Dark mode support
+
+Do you want to pick color in the dark? 
+Colorful supports dark mode :)
+
+![](https://github.com/hayashi311/Color-Picker-for-iOS/raw/screenshot/ColorPicker_Dark.png)
+
+
 ## How to use it
 
+It's designed like UIKit standard ui components.
+No surprise, You can use it as you think it.
+
 ### Podfile
 
 ```
@@ -29,26 +84,8 @@ colorPicker.set(color: .red, colorSpace: .extendedSRGB)
 view.add(subview: colorPicker)
 ```
 
-You can receive `.valueChanged` event when user changes color.
-
-## Reason why you choose colorful
+You can receive `.valueChanged` event when user changes color like ther UIKit's UIComponents.
 
-### Beautiful UI with haptic feedback.
-
-![](https://github.com/hayashi311/Color-Picker-for-iOS/raw/screenshot/ColorfulUI.gif)
-
-### Wide color space support
-
-| ColorSpace | Description |
-| :-------: | :---------: |
-| .extendedSRGB | The extended sRGB is color space for support wider and deeper representation of color. |
-| .sRGB | sRGB (standard Red Green Blue) is often the "default" color space for images that contain no color space information |
-
-![](https://github.com/hayashi311/Color-Picker-for-iOS/raw/screenshot/ColorPicker_ColorSpace.png)
-
-### Dark mode support
-
-![](https://github.com/hayashi311/Color-Picker-for-iOS/raw/screenshot/ColorPicker_Dark.png)
 
 ## Requirements