chore: docs Subclasser conventions

docs/README.md

@@ -2,4 +2,4 @@
 
 First be sure to understand our [definitions](./definitions.md).
 
-- [Guidelines for Styling](./guidelinesStyling.md)
+- [Guidelines for Styling](./guidelines-styling.md)

docs/subclasser-apis.md

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+# Subclasser apis
+
+In order to make it easy for Subclassers to extend our components, we follow a certain set
+of best practices naming conventions to make our code predictable.
+
+## Templates
+
+### Template naming conventions
+
+For template, we have the naming convention that every overridable template starts with an
+underscore and ends with
+
+### Seperation of concerns
+
+Our components should make it possible to override markup and styling, without having to redefine
+functionality.
+By using the spread directive, we can achieve this. For more info, see:
+[https://github.com/ing-bank/lion/issues/591](explanation).
+
+## Node references
+
+As a Subclasser, you sometimes need access to a protected node inside the shadow dom.
+Most functional nodes have their own getters. A Subclasser can acces those in his extension and
+in some cases, override these getters.
+
+### Node naming conventions
+
+A node reference will have an underscore prefix and always ends with `Node`.
+Examples are `_inputNode` and `_formNode`.