Fix Material theme

app/gui/main.qml

@@ -2,12 +2,16 @@ import QtQuick 2.9
 import QtQuick.Controls 2.2
 import QtQuick.Layouts 1.3
 
+import QtQuick.Controls.Material 2.1
+
 ApplicationWindow {
     id: window
     visible: true
     width: 1280
     height: 600
-    color: "#333333"
+
+    Material.theme: Material.Dark
+    Material.accent: Material.Purple
 
     StackView {
         id: stackView

app/gui/qtquickcontrols2.conf

@@ -1,6 +0,0 @@
-; This file can be edited to change the style of the application
-; Read "Qt Quick Controls 2 Configuration File" for details:
-; http://doc.qt.io/qt-5/qtquickcontrols2-configuration.html
-
-[Controls]
-Style=Material