moar docs

docs/examples/styles/margin.py

@@ -12,10 +12,16 @@ Where the fear has gone there will be nothing. Only I will remain."""
 
 class MarginApp(App):
     CSS = """
+
+    Screen {
+        background: white;
+        color: black;
+    }
    
     Static {
         margin: 4 8;  
         background: blue 20%;  
+        border: blue wide;
     }    
     
     """