E-book viewer: Remove extra spacing between document and scrollbars. This is particularly noticeable when using a dark theme for the viewer.

src/calibre/gui2/viewer/main.py

@@ -294,7 +294,6 @@ class EbookViewer(MainWindow):
         self.was_maximized = self.isMaximized()
         if not self.view.document.fullscreen_scrollbar:
             self.vertical_scrollbar.setVisible(False)
-        self.centralwidget.layout().setContentsMargins(0, 0, 0, 0)
 
         super(EbookViewer, self).showFullScreen()
 

src/calibre/gui2/viewer/ui.py

@@ -169,6 +169,7 @@ class Main(MainWindow):
         c.setObjectName('centralwidget')
         self.setCentralWidget(c)
         self.central_layout = cl = QGridLayout(c)
+        cl.setSpacing(0)
         c.setLayout(cl), cl.setContentsMargins(0, 0, 0, 0)
 
         self.view = v = DocumentView(self)