gtk4-demo: Add background to CSS Basics demo

So people can at least read the textview contents

diff --git a/demos/gtk-demo/css_basics.css b/demos/gtk-demo/css_basics.css
index 0b3365f50f78c46e441d2ca7fdf93597823a1a24..238ad466676515e7f03ea59ceac93daf255e4b0e 100644 (file)
--- a/demos/gtk-demo/css_basics.css
+++ b/demos/gtk-demo/css_basics.css
@@ -15,6 +15,10 @@
   border: 1px solid;
 }
 
+window {
+  background-color: white;
+}
+
 /* Make sure selections are visible */
 selection {
   background-color: darkGreen;