docs: Add documentation style guide for internal links

docs/README.md

@@ -8,3 +8,56 @@ For installation and contributing instructions, please follow the [Contributing
 
 1. Run `npm i` to install dependencies
 2. Run `npm run start` to start the website
+
+# Documentation Style Guide
+
+## Internal Links
+
+When adding or editing internal links, follow these conventions:
+
+### Do not include the `.md` extension
+
+Use paths without extensions. This avoids needing `index.md` for directory index pages and matches the web URL.
+
+```markdown
+<!-- Good -->
+[zones](/configuration/zones)
+[getting started](../guides/getting_started)
+
+<!-- Bad -->
+[zones](/configuration/zones.md)
+```
+
+### Use relative paths for same-directory links
+
+Use relative `./` paths for links to pages in the same directory.
+
+```markdown
+[zones](./zones)
+[masks](./masks)
+```
+
+### Use absolute paths for everything else
+
+For links outside the current directory, use absolute paths from the docs root. The exception is deeply nested subdirectories (e.g., `configuration/custom_classification/`) where `../` to the parent directory is acceptable.
+
+```markdown
+[object detectors](/configuration/object_detectors)
+[hardware](/frigate/hardware)
+[getting started](/guides/getting_started)
+
+<!-- Also OK from a nested subdirectory -->
+[zones](../zones)
+```
+
+### Never use full URLs for internal links
+
+```markdown
+<!-- Good -->
+[zones](/configuration/zones)
+
+<!-- Bad -->
+[zones](https://docs.frigate.video/configuration/zones)
+```
+
+> **Note:** Some existing links still use `.md` extensions. These should be updated when the file is being edited for other reasons.