Cocoa NSColor 安全色 / RGB 对照表

苹果在 Cocoa 里提供了若干安全色方便开发人员，统一界面风格，可惜这些颜色只给了值参考，在此整理一下。

Xcode Version： 9.2 (9C40b)
Swift Version：4

名称	RGB	颜色
`NSColor.black`	`#000000`
`NSColor.brown`	`#996633`
`NSColor.cyan`	`#00ffff`
`NSColor.darkGray`	`#555555`
`NSColor.gray`	`#808080`
`NSColor.green`	`#00ff00`
`NSColor.labelColor`	`#000000`
`NSColor.lightGray`	`#aaaaaa`
`NSColor.magenta`	`#ff00ff`
`NSColor.orange`	`#ff7f00`
`NSColor.purple`	`#7f007f`
`NSColor.quaternaryLabelColor`	`#000000`
`NSColor.orange`	`#ff7f00`
`NSColor.white`	`#ffffff`
`NSColor.yellow`	`#ffff00`
`NSColor.alternateSelectedControlColor`	`#0069d9`
`NSColor.alternateSelectedControlTextColor`	`#ffffff`
`NSColor.controlBackgroundColor`	`#ffffff`
`NSColor.controlColor`	`#e7e7e7`
`NSColor.controlHighlightColor`	`#e2e2e2`
`NSColor.controlLightHighlightColor`	`#ffffff`
`NSColor.controlShadowColor`	`#8d8d8d`
`NSColor.controlDarkShadowColor`	`#000000`
`NSColor.controlTextColor`	`#000000`
`NSColor.disabledControlTextColor`	`#000000`
`NSColor.gridColor`	`#cccccc`
`NSColor.headerColor`	`#aaaaaa`
`NSColor.headerTextColor`	`#000000`
`NSColor.highlightColor`	`#ffffff`
`NSColor.keyboardFocusIndicatorColor`	`#3b99fc`
`NSColor.knobColor`	`#9999bb`
`NSColor.scrollBarColor`	`#aaaaaa`
`NSColor.scrubberTexturedBackground`	`#ffffff`
`NSColor.secondarySelectedControlColor`	`#dcdcdc`
`NSColor.selectedControlColor`	`#b2d7ff`
`NSColor.selectedControlTextColor`	`#000000`
`NSColor.selectedTextColor`	`#000000`
`NSColor.selectedKnobColor`	`#666699`
`NSColor.shadowColor`	`#000000`
`NSColor.systemBlue`	`#1badf8`
`NSColor.systemBrown`	`#a2845e`
`NSColor.systemGray`	`#8e8e91`
`NSColor.systemGreen`	`#63da38`
`NSColor.systemOrange`	`#ff9500`
`NSColor.systemPink`	`#ff2968`
`NSColor.systemPurple`	`#cc73e1`
`NSColor.systemRed`	`#ff3b30`
`NSColor.systemYellow`	`#ffcc00`
`NSColor.textBackgroundColor`	`#ffffff`
`NSColor.textColor`	`#000000`
`NSColor.windowBackgroundColor`	`#ececec`
`NSColor.windowFrameColor`	`#aaaaaa`
`NSColor.windowFrameTextColor`	`#000000`
`NSColor.underPageBackgroundColor`	`#ffffff`