Fix bg color

mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/stylesheet/PrimaryStyleSheet.kt

@@ -38,7 +38,7 @@ class PrimaryStyleSheet : BaseStyleSheet() {
          * bot list
          */
         rootPane {
-            child(vBox) {
+            leftPane {
 
                 backgroundColor += c(primaryColor)
 //                这个padding有bug，十分神奇

mirai-console-graphical/src/main/kotlin/net/mamoe/mirai/console/graphical/view/PrimaryView.kt

@@ -30,6 +30,8 @@ class PrimaryView : View() {
 
         left = vbox {
 
+            addClass("left-pane")
+
             imageview(Image(PrimaryView::class.java.classLoader.getResourceAsStream("logo.png"))) {
                 fitHeight = 40.0
                 alignment = Pos.CENTER