add docs

Author: hipstersmoothie

.circleci/config.yml

@@ -3,7 +3,7 @@ version: 2.1
 defaults: &defaults
   working_directory: ~/postcss-themed
   docker:
-    - image: circleci/node:8.14-browsers
+    - image: circleci/node:10-browsers
   environment:
     TZ: '/usr/share/zoneinfo/America/Los_Angeles'
 

README.md

@@ -113,6 +113,45 @@ See [PostCSS] docs for examples for your environment.
 }
 ```
 
+### Theming with Objects
+
+You can even keep theme values in deeply nested objects.
+
+**Input:**
+
+```js
+const config = {
+  default: {
+    colors: {
+      primary: 'white',
+    },
+  },
+  other: {
+    colors: {
+      primary: 'black',
+    },
+  },
+};
+```
+
+```css
+.foo {
+  color: @theme colors.primary;
+}
+```
+
+**Output:**
+
+```css
+.foo {
+  color: white;
+}
+
+.other .foo {
+  color: black;
+}
+```
+
 ### Component themes
 
 Define a component level theme in either commonjs or typescript. A file names `themes.(js|ts)` must be co-located with the themeable CSS file.