feat(theme.json): 新增theme.json 说明，待完善

docs/collocation/themejson.md

+# theme.json
+
+> HBuilder X 4.18+ 支持
+
+### app
+
+使用步骤
+
+1. 在 `theme.json` 中定义相关变量
+2. 在 `pages.json` 中以@开头引用变量
+3. 可选在 `manifest.json -> app` 中配置主题默认值 `"defaultAppTheme": "light"`, 支持通过[主题API](https://doc.dcloud.net.cn/uni-app-x/api/theme.html)动态设置
+
+**注意：**
+- `iOS 13+`、`Android 10+`设备上才支持
+
+支持通过变量配置的属性如下所示：
+
+- 全局配置 globalStyle 与页面支持
+
+  - navigationBarBackgroundColor
+  - navigationBarTextStyle
+  - backgroundColor
+  - backgroundTextStyle
+
+- 全局配置 tabbar 属性：
+  - color
+  - selectedColor
+  - backgroundColor
+  - borderStyle
+  - list
+    - iconPath
+    - selectedIconPath
+
+## 变量配置文件 theme.json@themejson
+
+`theme.json` 用于颜色主题相关的变量定义，包含以下属性：
+
+| 属性  | 类型   | 必填 | 描述                 |
+| :---- | :----- | :--- | :------------------- |
+| light | Object | 是   | 浅色模式下的变量定义 |
+| dark  | Object | 是   | 深色模式下的变量定义 |
+
+示例如下：
+
+```json
+{
+	"light": {
+		"navBgColor": "#f8f8f8",
+		"navTxtStyle": "black"
+	},
+	"dark": {
+		"navBgColor": "#292929",
+		"navTxtStyle": "white"
+	}
+}
+```
+
+完成定义后，可在 `pages.json` 中全局配置或页面配置的相关属性中以 `@` 开头引用，例如：
+
+```json
+// 全局配置
+{
+  "globalStyle": {
+    "navigationBarBackgroundColor": "@navBgColor",
+    "navigationBarTextStyle": "@navTxtStyle"
+  }
+}
+// 页面配置
+{
+	"path": "pages/index/index",
+	"style":{
+		"navigationBarBackgroundColor": "@navBgColor",
+		"navigationBarTextStyle": "@navTxtStyle"
+	}
+}
+```
+
+配置完成后，调用相应 api 框架会自动所设属性，展示对应主题下的颜色。
+
+## 配置示例@themeconfig
+
+pages.json（示例省略了主题相关以外的配置项）
+
+```json
+{
+	"globalStyle": {
+		"navigationBarBackgroundColor": "@navBgColor",
+		"navigationBarTextStyle": "@navTxtStyle",
+		"backgroundColor": "@bgColor",
+		"backgroundTextStyle": "@bgTxtStyle"
+	},
+	"tabBar": {
+		"color": "@tabFontColor",
+		"selectedColor": "@tabSelectedColor",
+		"backgroundColor": "@tabBgColor",
+		"borderStyle": "@tabBorderStyle",
+		"list": [
+			{
+				"iconPath": "@iconPath1",
+				"selectedIconPath": "@selectedIconPath1"
+			},
+			{
+				"iconPath": "@iconPath2",
+				"selectedIconPath": "@selectedIconPath2"
+			}
+		]
+	}
+}
+```
+
+theme.json
+
+```json
+{
+	"light": {
+		"navBgColor": "#f8f8f8",
+		"navTxtStyle": "black",
+		"bgColor": "#ffffff",
+		"bgTxtStyle": "light",
+		"bgColorTop": "#eeeeee",
+		"bgColorBottom": "#efefef",
+		"tabFontColor": "#000000",
+		"tabSelectedColor": "#3cc51f",
+		"tabBgColor": "#ffffff",
+		"tabBorderStyle": "black",
+		"iconPath1": "/static/icon1_light.png",
+		"selectedIconPath1": "/static/selected_icon1_light.png",
+		"iconPath2": "/static/icon2_light.png",
+		"selectedIconPath2": "/static/selected_icon2_light.png"
+	},
+	"dark": {
+		"navBgColor": "#292929",
+		"navTxtStyle": "white",
+		"bgColor": "#1f1f1f",
+		"bgTxtStyle": "dark",
+		"bgColorTop": "#292929",
+		"bgColorBottom": "#1f1f1f",
+		"tabFontColor": "#ffffff",
+		"tabSelectedColor": "#51a937",
+		"tabBgColor": "#292929",
+		"tabBorderStyle": "white",
+		"iconPath1": "/static/icon1_dark.png",
+		"selectedIconPath1": "/static/selected_icon1_dark.png",
+		"iconPath2": "/static/icon2_dark.png",
+		"selectedIconPath2": "/static/selected_icon2_dark.png"
+	}
+}
+```