qutebrowser: add user stylesheet+change bg colour

replace the default 'white' bg and make sure that text colour is changed
accordingly for 'body > pre' elements that contain e.g. raw code on
gitea/github

.config/qutebrowser/config.py

@@ -179,6 +179,10 @@ config.set('content.javascript.enabled', True, 'qute://*/*')
 # Type: Bool
 c.content.pdfjs = False
 
+# List of user stylesheet filenames to use.
+# Type: List of File, or File
+c.content.user_stylesheets = 'stylesheets/user.css'
+
 # CSS selectors used to determine which elements on a page should have
 # hints.
 # Type: Dict
@@ -230,7 +234,7 @@ c.zoom.levels = ['25%', '33%', '50%', '67%', '75%', '90%', '100%', '110%', '120%
 # Background color for webpages if unset (or empty to use the theme's
 # color).
 # Type: QtColor
-c.colors.webpage.bg = 'white'
+c.colors.webpage.bg = '#1c1b22'
 
 # Default font size to use. Whenever "default_size" is used in a font
 # setting, it's replaced with the size listed here. Valid values are

.config/qutebrowser/stylesheets/user.css

@@ -0,0 +1,7 @@
+/* gitea/github raw code sites */
+body > pre
+{
+	color: #fbfbfe !important;
+	background-color: #1c1b22 !important;
+	background: #1c1b22 !important;
+}