Fix scroll page

CHANGELOG.md

@@ -31,6 +31,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - Fix crash when `validate_on` value isn't a set https://github.com/Textualize/textual/pull/4868
 - Fix `Input.cursor_blink` having no effect on the blink cycle after mounting https://github.com/Textualize/textual/pull/4869
+- Fixed scrolling by page not taking scrollbar in to account https://github.com/Textualize/textual/pull/4916
 
 ## [0.76.0]
 

src/textual/widget.py

@@ -2647,7 +2647,7 @@ def scroll_page_up(
             level: Minimum level required for the animation to take place (inclusive).
         """
         self.scroll_to(
-            y=self.scroll_y - self.container_size.height,
+            y=self.scroll_y - self.scrollable_content_region.height,
             animate=animate,
             speed=speed,
             duration=duration,
@@ -2680,7 +2680,7 @@ def scroll_page_down(
             level: Minimum level required for the animation to take place (inclusive).
         """
         self.scroll_to(
-            y=self.scroll_y + self.container_size.height,
+            y=self.scroll_y + self.scrollable_content_region.height,
             animate=animate,
             speed=speed,
             duration=duration,
@@ -2715,7 +2715,7 @@ def scroll_page_left(
         if speed is None and duration is None:
             duration = 0.3
         self.scroll_to(
-            x=self.scroll_x - self.container_size.width,
+            x=self.scroll_x - self.scrollable_content_region.width,
             animate=animate,
             speed=speed,
             duration=duration,
@@ -2750,7 +2750,7 @@ def scroll_page_right(
         if speed is None and duration is None:
             duration = 0.3
         self.scroll_to(
-            x=self.scroll_x + self.container_size.width,
+            x=self.scroll_x + self.scrollable_content_region.width,
             animate=animate,
             speed=speed,
             duration=duration,