adjusted GridBagLayout for Restart button

src/main/java/Gui/GameGui.java

@@ -131,10 +131,15 @@ GridBagConstraints gbc;
 	@Override
 	public void createRestartButton() {
 		GridBagConstraints gbc = new GridBagConstraints();
+		gbc.gridwidth = GridBagConstraints.REMAINDER;
+        gbc.fill = GridBagConstraints.HORIZONTAL;
+        gbc.ipadx = 200;
+        gbc.ipady = 100;
+        gbc.insets = new Insets(20, 0, 0, 0);
 		RestartBtn = new JButton("Neustarten");
+		
 		LosingPanel.add(LosingLabel,gbc);
 		LosingPanel.add(RestartBtn,gbc);
-
 		RestartBtn.addActionListener(new RestartGame());
 	}
 }