proposal: global variables (#299)

Author: chdeskur

fern/products/docs/docs.yml

@@ -79,6 +79,9 @@ navigation:
         path: ./pages/component-library/custom-components/reusable-markdown.mdx
       - page: Custom React Components
         path: ./pages/component-library/custom-components/custom-react-components.mdx
+      - page: Global Variables
+        hidden: true
+        path: ./pages/component-library/custom-components/global-variables.mdx
   - section: Customization
     collapsed: true
     contents:

fern/products/docs/pages/component-library/custom-components/global-variables.mdx

@@ -0,0 +1,79 @@
+---
+title: Global Variables
+---
+
+<Warning>
+Global variables are not yet available. Please contact [email protected] if you have any feedback or questions.
+</Warning>
+
+Global variables allow you to maintain consistency across your documentation and make updates easier by centralizing commonly used values. You can define and use global variables in several places within Fern documentation. 
+
+## Define global variables
+
+Define global variables in your `docs.yml` file:
+
+```yaml docs.yml
+variables:
+  - name: "API_VERSION"
+    value: "v1"
+  - name: "API_URL"
+    value: "https://api.example.com"
+```
+
+## Use variables in content
+
+Reference variables throughout your MDX content using double angle brackets:
+
+### In Markdown
+
+````mdx use-api.mdx
+Use the latest version of the API: <<API_VERSION>>
+
+```bash
+curl -X GET <<API_URL>>/api/<<API_VERSION>>/users
+```
+````
+
+### In API references
+
+```yaml openapi.yml
+paths:
+  /users:
+    get:
+      description: | 
+        The API version is <<API_VERSION>>
+      responses:
+        '200':
+          description: "Success"
+          content:
+            application/json:
+              schema:
+```
+
+### In docs.yml configuration
+
+You can also use variables in your `docs.yml` configuration.
+
+```yaml docs.yml
+variables:
+  - name: "ADMIN_ROLE_NAME"
+    value: "admin"
+```
+
+```yaml docs.yml
+roles:
+  - everyone
+  - <<ADMIN_ROLE_NAME>>
+
+navigation:
+  - tab: Admin
+    layout:
+      - page: Admin Dashboard
+        path: pages/admin-dashboard.mdx
+        viewers:
+          - <<ADMIN_ROLE_NAME>>
+```
+
+<Note>
+Fern will not render variables in your content if they are not defined in your `docs.yml` configuration. Instead, the variable will be rendered as a literal string.
+</Note>