Remove unused docks code

src/textual/_arrange.py

@@ -98,7 +98,7 @@ def arrange(
             )
 
         dock_spacing = Spacing(top, right, bottom, left)
-        region = size.region.shrink(dock_spacing)
+        region = region.shrink(dock_spacing)
         layout_placements, arranged_layout_widgets = widget._layout.arrange(
             widget, layout_widgets, region.size
         )

src/textual/css/_style_properties.py

@@ -511,45 +511,6 @@ class SpacingProperty:
                 obj.refresh(layout=True)
 
 
-class DocksProperty:
-    """Descriptor for getting and setting the docks property. This property
-    is used to define docks and their location on screen.
-    """
-
-    def __get__(
-        self, obj: StylesBase, objtype: type[StylesBase] | None = None
-    ) -> tuple[DockGroup, ...]:
-        """Get the Docks property
-
-        Args:
-            obj (Styles): The ``Styles`` object.
-            objtype (type[Styles]): The ``Styles`` class.
-
-        Returns:
-            tuple[DockGroup, ...]: A ``tuple`` containing the defined docks.
-        """
-        if obj.has_rule("docks"):
-            return obj.get_rule("docks")
-        from .styles import DockGroup
-
-        return (DockGroup("_default", "top", 1),)
-
-    def __set__(self, obj: StylesBase, docks: Iterable[DockGroup] | None):
-        """Set the Docks property
-
-        Args:
-            obj (Styles): The ``Styles`` object.
-            docks (Iterable[DockGroup]): Iterable of DockGroups
-        """
-        _rich_traceback_omit = True
-        if docks is None:
-            if obj.clear_rule("docks"):
-                obj.refresh(layout=True)
-        else:
-            if obj.set_rule("docks", tuple(docks)):
-                obj.refresh(layout=True)
-
-
 class DockProperty:
     """Descriptor for getting and setting the dock property. The dock property
     allows you to specify which edge you want to fix a Widget to.

src/textual/css/styles.py

@@ -21,7 +21,6 @@ from ._style_properties import (
     BoxProperty,
     ColorProperty,
     DockProperty,
-    DocksProperty,
     FractionalProperty,
     IntegerProperty,
     LayoutProperty,
@@ -720,14 +719,6 @@ class Styles(StylesBase):
             append_declaration("offset", f"{x} {y}")
         if has_rule("dock"):
             append_declaration("dock", rules["dock"])
-        if has_rule("docks"):
-            append_declaration(
-                "docks",
-                " ".join(
-                    (f"{name}={edge}/{z}" if z else f"{name}={edge}")
-                    for name, edge, z in rules["docks"]
-                ),
-            )
         if has_rule("layers"):
             append_declaration("layers", " ".join(self.layers))
         if has_rule("layer"):