[gnome-tour/pan-tour-fullcolor] add a generic page style class

[Bilal Elmoussaoui <bilelmoussaoui src gnome org>]

commit 852881d87efa743104fdae47c4081a333bd91e4d
Author: Bilal Elmoussaoui <bil elmoussaoui gmail com>
Date:   Wed Jan 20 14:24:07 2021 +0100

    add a generic page style class

 src/widgets/pages/image.rs   | 1 +
 src/widgets/pages/welcome.rs | 2 ++
 2 files changed, 3 insertions(+)
---
diff --git a/src/widgets/pages/image.rs b/src/widgets/pages/image.rs
index 85c6511..d53ee5c 100644
--- a/src/widgets/pages/image.rs
+++ b/src/widgets/pages/image.rs
@@ -16,6 +16,7 @@ impl ImagePageWidget {
 
     fn init(&self, resource_uri: &str, head: String, body: String) {
         self.widget.set_property_expand(true);
+        self.widget.get_style_context().add_class("page");
         self.widget.set_halign(gtk::Align::Fill);
         self.widget.set_valign(gtk::Align::Fill);
 
diff --git a/src/widgets/pages/welcome.rs b/src/widgets/pages/welcome.rs
index 130b2d8..59b6623 100644
--- a/src/widgets/pages/welcome.rs
+++ b/src/widgets/pages/welcome.rs
@@ -73,6 +73,8 @@ impl WelcomePageWidget {
             .margin_top(24)
             .margin_bottom(24)
             .build();
+        self.widget.get_style_context().add_class("page");
+        self.widget.get_style_context().add_class("welcome-page");
 
         #[cfg(not(feature = "video"))]
         let header = {