Merge pull request #727 from Textualize/default-css

Default css

tests/css/test_stylesheet.py

@@ -106,16 +106,18 @@ def test_stylesheet_apply_user_css_over_widget_css():
     user_css = ".a {color: red; tint: yellow;}"
 
     class MyWidget(Widget):
-        CSS = ".a {color: blue !important; background: lime;}"
+        DEFAULT_CSS = ".a {color: blue !important; background: lime;}"
 
     node = MyWidget()
     node.add_class("a")
 
     stylesheet = _make_user_stylesheet(user_css)
-    stylesheet.add_source(MyWidget.CSS, "widget.py:MyWidget", is_default_css=True)
+    stylesheet.add_source(
+        MyWidget.DEFAULT_CSS, "widget.py:MyWidget", is_default_css=True
+    )
     stylesheet.apply(node)
 
-    # The node is red because user CSS overrides Widget.CSS
+    # The node is red because user CSS overrides Widget.DEFAULT_CSS
     assert node.styles.color == Color(255, 0, 0)
     # The background colour defined in the Widget still applies, since user CSS doesn't override it
     assert node.styles.background == Color(0, 255, 0)

tests/test_integration_layout.py

@@ -110,7 +110,7 @@ async def test_composition_of_vertical_container_with_children(
     expected_placeholders_offset_x: int,
 ):
     class VerticalContainer(Widget):
-        CSS = (
+        DEFAULT_CSS = (
             """
         VerticalContainer {
             layout: vertical;
@@ -304,7 +304,7 @@ async def test_scrollbar_size_impact_on_the_layout(
     class LargeWidgetContainer(Widget):
         # TODO: Once textual#581 ("Default versus User CSS") is solved the following CSS should just use the
         #  "LargeWidgetContainer" selector, without having to use a more specific one to be able to override Widget's CSS:
-        CSS = """
+        DEFAULT_CSS = """
         #large-widget-container {
             width: 20;
             height: 20;

tests/test_integration_scrolling.py

@@ -48,7 +48,7 @@ async def test_scroll_to_widget(
     last_screen_expected_placeholder_ids: Sequence[int],
 ):
     class VerticalContainer(Widget):
-        CSS = """
+        DEFAULT_CSS = """
         VerticalContainer {
             layout: vertical;
             overflow: hidden auto;
@@ -60,7 +60,7 @@ async def test_scroll_to_widget(
         """
 
     class MyTestApp(AppTest):
-        CSS = """
+        DEFAULT_CSS = """
         Placeholder {
             height: 5; /* minimal height to see the name of a Placeholder */
         }