diff --git a/src/main/gtk-3.0/gtk-dark-blue.css b/src/main/gtk-3.0/gtk-dark-blue.css
index 9068d9d..ad50bad 100644
--- a/src/main/gtk-3.0/gtk-dark-blue.css
+++ b/src/main/gtk-3.0/gtk-dark-blue.css
@@ -7255,7 +7255,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-green.css b/src/main/gtk-3.0/gtk-dark-green.css
index 468f654..0ba8327 100644
--- a/src/main/gtk-3.0/gtk-dark-green.css
+++ b/src/main/gtk-3.0/gtk-dark-green.css
@@ -7255,7 +7255,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-grey.css b/src/main/gtk-3.0/gtk-dark-grey.css
index 2c969a5..7611f99 100644
--- a/src/main/gtk-3.0/gtk-dark-grey.css
+++ b/src/main/gtk-3.0/gtk-dark-grey.css
@@ -7255,7 +7255,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-orange.css b/src/main/gtk-3.0/gtk-dark-orange.css
index ccce8e3..3e2583d 100644
--- a/src/main/gtk-3.0/gtk-dark-orange.css
+++ b/src/main/gtk-3.0/gtk-dark-orange.css
@@ -7255,7 +7255,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-pink.css b/src/main/gtk-3.0/gtk-dark-pink.css
index de41e1c..1ce3861 100644
--- a/src/main/gtk-3.0/gtk-dark-pink.css
+++ b/src/main/gtk-3.0/gtk-dark-pink.css
@@ -7255,7 +7255,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-purple.css b/src/main/gtk-3.0/gtk-dark-purple.css
index f010770..2db3709 100644
--- a/src/main/gtk-3.0/gtk-dark-purple.css
+++ b/src/main/gtk-3.0/gtk-dark-purple.css
@@ -7255,7 +7255,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-red.css b/src/main/gtk-3.0/gtk-dark-red.css
index 6a17b48..f43545f 100644
--- a/src/main/gtk-3.0/gtk-dark-red.css
+++ b/src/main/gtk-3.0/gtk-dark-red.css
@@ -7255,7 +7255,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-solid-blue.css b/src/main/gtk-3.0/gtk-dark-solid-blue.css
index 310d427..ebb1bab 100644
--- a/src/main/gtk-3.0/gtk-dark-solid-blue.css
+++ b/src/main/gtk-3.0/gtk-dark-solid-blue.css
@@ -7259,7 +7259,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-solid-green.css b/src/main/gtk-3.0/gtk-dark-solid-green.css
index 0d867fa..3bff990 100644
--- a/src/main/gtk-3.0/gtk-dark-solid-green.css
+++ b/src/main/gtk-3.0/gtk-dark-solid-green.css
@@ -7259,7 +7259,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-solid-grey.css b/src/main/gtk-3.0/gtk-dark-solid-grey.css
index 404f715..d632c6a 100644
--- a/src/main/gtk-3.0/gtk-dark-solid-grey.css
+++ b/src/main/gtk-3.0/gtk-dark-solid-grey.css
@@ -7259,7 +7259,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-solid-orange.css b/src/main/gtk-3.0/gtk-dark-solid-orange.css
index 1a0153c..144b7bc 100644
--- a/src/main/gtk-3.0/gtk-dark-solid-orange.css
+++ b/src/main/gtk-3.0/gtk-dark-solid-orange.css
@@ -7259,7 +7259,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-solid-pink.css b/src/main/gtk-3.0/gtk-dark-solid-pink.css
index f887143..a98debd 100644
--- a/src/main/gtk-3.0/gtk-dark-solid-pink.css
+++ b/src/main/gtk-3.0/gtk-dark-solid-pink.css
@@ -7259,7 +7259,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-solid-purple.css b/src/main/gtk-3.0/gtk-dark-solid-purple.css
index d73f756..3a16f15 100644
--- a/src/main/gtk-3.0/gtk-dark-solid-purple.css
+++ b/src/main/gtk-3.0/gtk-dark-solid-purple.css
@@ -7259,7 +7259,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-solid-red.css b/src/main/gtk-3.0/gtk-dark-solid-red.css
index 75e1d46..c2111e8 100644
--- a/src/main/gtk-3.0/gtk-dark-solid-red.css
+++ b/src/main/gtk-3.0/gtk-dark-solid-red.css
@@ -7259,7 +7259,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-solid-yellow.css b/src/main/gtk-3.0/gtk-dark-solid-yellow.css
index 7694906..5a4ff54 100644
--- a/src/main/gtk-3.0/gtk-dark-solid-yellow.css
+++ b/src/main/gtk-3.0/gtk-dark-solid-yellow.css
@@ -7259,7 +7259,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-solid.css b/src/main/gtk-3.0/gtk-dark-solid.css
index 3eee88c..9325d06 100644
--- a/src/main/gtk-3.0/gtk-dark-solid.css
+++ b/src/main/gtk-3.0/gtk-dark-solid.css
@@ -7259,7 +7259,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark-yellow.css b/src/main/gtk-3.0/gtk-dark-yellow.css
index 0fa8a7f..adef04f 100644
--- a/src/main/gtk-3.0/gtk-dark-yellow.css
+++ b/src/main/gtk-3.0/gtk-dark-yellow.css
@@ -7255,7 +7255,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-dark.css b/src/main/gtk-3.0/gtk-dark.css
index cad4dbf..ef38812 100644
--- a/src/main/gtk-3.0/gtk-dark.css
+++ b/src/main/gtk-3.0/gtk-dark.css
@@ -7255,7 +7255,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #242424;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-blue.css b/src/main/gtk-3.0/gtk-light-blue.css
index 4584fd9..48321af 100644
--- a/src/main/gtk-3.0/gtk-light-blue.css
+++ b/src/main/gtk-3.0/gtk-light-blue.css
@@ -7271,7 +7271,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-green.css b/src/main/gtk-3.0/gtk-light-green.css
index 65517fd..f7ca4e2 100644
--- a/src/main/gtk-3.0/gtk-light-green.css
+++ b/src/main/gtk-3.0/gtk-light-green.css
@@ -7271,7 +7271,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-grey.css b/src/main/gtk-3.0/gtk-light-grey.css
index d7a295e..ed26ff2 100644
--- a/src/main/gtk-3.0/gtk-light-grey.css
+++ b/src/main/gtk-3.0/gtk-light-grey.css
@@ -7271,7 +7271,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-orange.css b/src/main/gtk-3.0/gtk-light-orange.css
index 6891d20..cad8335 100644
--- a/src/main/gtk-3.0/gtk-light-orange.css
+++ b/src/main/gtk-3.0/gtk-light-orange.css
@@ -7271,7 +7271,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-pink.css b/src/main/gtk-3.0/gtk-light-pink.css
index 3ee1c96..7794d7c 100644
--- a/src/main/gtk-3.0/gtk-light-pink.css
+++ b/src/main/gtk-3.0/gtk-light-pink.css
@@ -7271,7 +7271,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-purple.css b/src/main/gtk-3.0/gtk-light-purple.css
index ed9f0ea..3644969 100644
--- a/src/main/gtk-3.0/gtk-light-purple.css
+++ b/src/main/gtk-3.0/gtk-light-purple.css
@@ -7271,7 +7271,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-red.css b/src/main/gtk-3.0/gtk-light-red.css
index f7d096e..5674a0d 100644
--- a/src/main/gtk-3.0/gtk-light-red.css
+++ b/src/main/gtk-3.0/gtk-light-red.css
@@ -7271,7 +7271,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-solid-blue.css b/src/main/gtk-3.0/gtk-light-solid-blue.css
index bc5fee7..bc06150 100644
--- a/src/main/gtk-3.0/gtk-light-solid-blue.css
+++ b/src/main/gtk-3.0/gtk-light-solid-blue.css
@@ -7275,7 +7275,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-solid-green.css b/src/main/gtk-3.0/gtk-light-solid-green.css
index b98e331..17ef0b0 100644
--- a/src/main/gtk-3.0/gtk-light-solid-green.css
+++ b/src/main/gtk-3.0/gtk-light-solid-green.css
@@ -7275,7 +7275,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-solid-grey.css b/src/main/gtk-3.0/gtk-light-solid-grey.css
index a335b0e..a168cb5 100644
--- a/src/main/gtk-3.0/gtk-light-solid-grey.css
+++ b/src/main/gtk-3.0/gtk-light-solid-grey.css
@@ -7275,7 +7275,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-solid-orange.css b/src/main/gtk-3.0/gtk-light-solid-orange.css
index a913440..7428853 100644
--- a/src/main/gtk-3.0/gtk-light-solid-orange.css
+++ b/src/main/gtk-3.0/gtk-light-solid-orange.css
@@ -7275,7 +7275,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-solid-pink.css b/src/main/gtk-3.0/gtk-light-solid-pink.css
index c20a422..4bbe658 100644
--- a/src/main/gtk-3.0/gtk-light-solid-pink.css
+++ b/src/main/gtk-3.0/gtk-light-solid-pink.css
@@ -7275,7 +7275,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-solid-purple.css b/src/main/gtk-3.0/gtk-light-solid-purple.css
index be1f5df..e333a71 100644
--- a/src/main/gtk-3.0/gtk-light-solid-purple.css
+++ b/src/main/gtk-3.0/gtk-light-solid-purple.css
@@ -7275,7 +7275,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-solid-red.css b/src/main/gtk-3.0/gtk-light-solid-red.css
index f637ad9..3199334 100644
--- a/src/main/gtk-3.0/gtk-light-solid-red.css
+++ b/src/main/gtk-3.0/gtk-light-solid-red.css
@@ -7275,7 +7275,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-solid-yellow.css b/src/main/gtk-3.0/gtk-light-solid-yellow.css
index fdd36e6..47aa4f3 100644
--- a/src/main/gtk-3.0/gtk-light-solid-yellow.css
+++ b/src/main/gtk-3.0/gtk-light-solid-yellow.css
@@ -7275,7 +7275,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-solid.css b/src/main/gtk-3.0/gtk-light-solid.css
index f92cfe3..23cba89 100644
--- a/src/main/gtk-3.0/gtk-light-solid.css
+++ b/src/main/gtk-3.0/gtk-light-solid.css
@@ -7275,7 +7275,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light-yellow.css b/src/main/gtk-3.0/gtk-light-yellow.css
index 2dae4d2..e07567e 100644
--- a/src/main/gtk-3.0/gtk-light-yellow.css
+++ b/src/main/gtk-3.0/gtk-light-yellow.css
@@ -7271,7 +7271,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/main/gtk-3.0/gtk-light.css b/src/main/gtk-3.0/gtk-light.css
index b928cbc..84a0d30 100644
--- a/src/main/gtk-3.0/gtk-light.css
+++ b/src/main/gtk-3.0/gtk-light.css
@@ -7271,7 +7271,8 @@ window#GearyMainWindow.background.csd > overlay > box.vertical > paned > .sideba
 
 .geary-main-window.background.csd stack#conversation_viewer,
 window#GearyMainWindow.background.csd stack#conversation_viewer {
-  border-bottom-right-radius: 12px;
+  background-color: #ffffff;
+  border-bottom-right-radius: 13px;
 }
 
 .geary-main-window.background.csd stack#conversation_viewer scrolledwindow.geary-conversation-scroller viewport.frame,
diff --git a/src/sass/gtk/_applications.scss b/src/sass/gtk/_applications.scss
index e489fcc..253a990 100644
--- a/src/sass/gtk/_applications.scss
+++ b/src/sass/gtk/_applications.scss
@@ -2773,10 +2773,7 @@ window#whiskermenu-window {
   }
 }
 
-//
-//  * Thunar *
-//
-
+// Thunar
 window.background.csd.thunar {
   > grid.horizontal > paned.horizontal > scrolledwindow.frame.sidebar.shortcuts-pane {
     border-bottom-left-radius: $wm_radius;
@@ -2894,7 +2891,8 @@ window#GearyMainWindow.background.csd {
   }
 
   stack#conversation_viewer {
-    border-bottom-right-radius: $wm_radius;
+    background-color: $base_color;
+    border-bottom-right-radius: $wm_radius + 1px;
 
     scrolledwindow.geary-conversation-scroller {
       viewport.frame {