Add a note to the docs about styling tabs

Note that I can't tell if this comes out as I'd like, as right at the moment
I can't locally serve the docs due to an error during documentation
generation (an issue confirmed by @rodrigogiraoserrao).

docs/examples/widgets/tabbed_content_label_color.py

@@ -0,0 +1,25 @@
+from textual.app import App, ComposeResult
+from textual.widgets import Label, TabbedContent, TabPane
+
+
+class ColorTabsApp(App):
+    CSS = """
+    TabbedContent #--content-tab-green {
+        color: green;
+    }
+
+    TabbedContent #--content-tab-red {
+        color: red;
+    }
+    """
+
+    def compose(self) -> ComposeResult:
+        with TabbedContent():
+            with TabPane("Red", id="red"):
+                yield Label("Red!")
+            with TabPane("Green", id="green"):
+                yield Label("Green!")
+
+
+if __name__ == "__main__":
+    ColorTabsApp().run()

docs/widgets/tabbed_content.md

@@ -94,6 +94,30 @@ The following example contains a `TabbedContent` with three tabs.
     --8<-- "docs/examples/widgets/tabbed_content.py"
     ```
 
+## Styling
+
+The `TabbedContent` widget is composed of two main sub-widgets: a
+[`Tabs`](tabs.md) and a [`ContentSwitcher`]((content_switcher.md)); you can
+style them accordingly.
+
+The tabs within the `Tabs` widget will have prefixed IDs; each ID being the
+ID of the `TabPane` the `Tab` is for, prefixed with `--content-tab-`. If you
+wish to style individual tabs within the `TabbedContent` widget you will
+need to use that prefix for the `Tab` IDs.
+
+For example, to create a `TabbedContent` that has red and green labels:
+
+=== "Output"
+
+    ```{.textual path="docs/examples/widgets/tabbed_content_label_color.py"}
+    ```
+
+=== "tabbed_content.py"
+
+    ```python
+    --8<-- "docs/examples/widgets/tabbed_content_label_color.py"
+    ```
+
 ## Reactive Attributes
 
 | Name     | Type  | Default | Description                                                    |