Clarify that theme does not set a default dark/light color mode

fern/products/api-def/openapi/extensions/method-names.mdx

@@ -69,3 +69,29 @@ api:
 ```
 
 `x-fern-sdk-group-name` and `x-fern-sdk-method-name` still take precedence, so you can group individual endpoints while ignoring tags elsewhere. Enabling `ignore-tags` avoids editing the spec or maintaining overlays when tags would otherwise produce awkward sub-clients, such as a `ConversationsV2Configuration` tag becoming a `conversations_v2_configuration` sub-client.
+
+### Namespacing schemas with `x-fern-sdk-namespace`
+
+`x-fern-sdk-namespace` namespaces the type IDs of every schema in a spec. When two specs both define a `Team` type, giving one spec `x-fern-sdk-namespace: entity_manager` makes Fern reference its `Team` as `entity_manager:Team` internally, so the two types no longer collide.
+
+`x-fern-sdk-group-name` and `x-fern-sdk-namespace` solve different problems. `x-fern-sdk-group-name` organizes endpoints into client sub-resources (`client.users.create()`). `x-fern-sdk-namespace` prevents schema name collisions when multiple API specs define types with the same name.
+
+The extension applies to a whole spec, not to individual endpoints. Set it at the root of the OpenAPI file:
+
+```yaml title="entity-manager.yaml" {2}
+openapi: 3.1.0
+x-fern-sdk-namespace: entity_manager
+info:
+  title: Entity Manager
+```
+
+Equivalently, set [`namespace`](/learn/sdks/reference/generators-yml#namespace) on the spec entry in `generators.yml`. This value takes precedence over the extension when both are present:
+
+```yaml title="generators.yml" {4, 6}
+api:
+  specs:
+    - openapi: ./openapi/entity-manager.yaml
+      namespace: entity_manager
+    - openapi: ./openapi/task-manager.yaml
+      namespace: task_manager
+```

fern/products/api-def/openapi/extensions/overview.md

@@ -35,6 +35,7 @@ The table below shows all available extensions and links to detailed documentati
 | [`x-fern-pagination`](./pagination) | Configure auto-pagination for list endpoints |
 | [`x-fern-sdk-method-name`](./method-names) | Customize SDK method names |
 | [`x-fern-sdk-group-name`](./method-names) | Organize methods into SDK groups |
+| [`x-fern-sdk-namespace`](./method-names#namespacing-schemas-with-x-fern-sdk-namespace) | Namespace schemas to prevent name collisions when combining multiple API specs |
 | [`x-fern-sdk-variables`](./sdk-variables) | Set common path parameters across all requests |
 | [`x-fern-parameter-name`](./parameter-names) | Customize parameter variable names |
 | [`x-fern-property-name`](./property-names) | Customize object property variable names |

fern/products/docs/pages/navigation/site-level-settings.mdx

@@ -670,6 +670,14 @@ layout:
 
 Customize the visual style of specific UI elements across your documentation site.
 
+<Note title="Setting a default color mode">
+  The `theme` key styles UI elements (sidebar, body, tabs). It does not control the light/dark color mode. Fern follows the visitor's operating system preference, and no `docs.yml` key forces the site into dark or light mode for all visitors. The closest options are:
+
+  - [`settings.dark-mode-code: true`](#settings-configuration) renders code blocks in dark mode regardless of the visitor's color mode.
+  - [`<Fern.ThemeSwitch />`](/learn/docs/customization/header-and-footer) in a custom header lets visitors toggle between modes.
+  - [`colors`](#colors-configuration) with both `light` and `dark` values for `accent-primary` and other color keys keeps your brand consistent in both modes.
+</Note>
+
 ```yaml docs.yml
 theme:
   sidebar: minimal

fern/products/docs/pages/preview-publish/preview-changes-locally.mdx

@@ -122,6 +122,12 @@ If your docs use [role-based access control](/learn/docs/authentication/features
 
 Preview links persist indefinitely — Fern doesn't auto-expire them. Any organization member can use [`fern docs preview list`](/learn/cli-api-reference/cli-reference/docs-commands#fern-docs-preview-list) to see active previews and [`fern docs preview delete`](/learn/cli-api-reference/cli-reference/docs-commands#fern-docs-preview-delete) to remove them when they're no longer needed. To clean up previews automatically when PRs merge, set up a [GitHub Actions workflow](#clean-up-preview-links-when-prs-merge).
 
+Previews created without `--id` have no identifier to pass to `--id`. To delete one, pass its full preview URL instead:
+
+```bash
+fern docs preview delete https://fern-preview-c973a36e-337b-44f5-ab83-aab.docs.buildwithfern.com
+```
+
 ### Automate with GitHub Actions
 
 You can use a GitHub Actions workflow to automatically generate a preview URL when a pull request is opened. By passing `--id` with the branch name, every push to the same PR updates the same preview URL instead of creating a new one. The workflow posts a comment on the PR with the preview link and direct links to every page changed in the PR, so reviewers can jump straight to affected pages.
@@ -351,3 +357,9 @@ jobs:
           fern docs preview delete --id "${{ github.head_ref }}" || echo "Preview deletion returned non-zero — it may already be gone"
 ```
 </CodeBlock>
+
+## Deleting published production docs
+
+There is no single command to delete a production site. Published docs stay live as long as the site is configured in `docs.yml`. To take a site offline entirely, contact [support@buildwithfern.com](mailto:support@buildwithfern.com).
+
+To remove specific pages, delete them from the navigation in `docs.yml` (or mark them [`hidden: true`](/learn/docs/configuration/navigation#hiding-content) to keep them reachable by direct URL only) and republish with `fern generate --docs`. Pages removed from navigation are no longer reachable, so add a [redirect](/learn/docs/seo/redirects) from the old path to avoid broken links.