Fix background color on the room list widget

resources/styles/nheko-dark.qss

@@ -48,6 +48,10 @@ RoomList > * {
     border: none;
 }
 
+#roomlist_area {
+    background-color: #2d3139;
+}
+
 CommunitiesList,
 CommunitiesList > * {
     background-color: #2d3139;

resources/styles/nheko.qss

@@ -48,6 +48,10 @@ RoomList > * {
     border: none;
 }
 
+#roomlist_area {
+    background-color: white;
+}
+
 CommunitiesList,
 CommunitiesList > * {
     background-color: white;

src/RoomList.cpp

@@ -51,6 +51,7 @@ RoomList::RoomList(QSharedPointer<UserSettings> userSettings, QWidget *parent)
 #endif
 
         scrollAreaContents_ = new QWidget(this);
+        scrollAreaContents_->setObjectName("roomlist_area");
 
         contentsLayout_ = new QVBoxLayout(scrollAreaContents_);
         contentsLayout_->setSpacing(0);