unity3d 修改gui label颜色，定义颜色需除以256

 GUIStyle titleStyle2 = new GUIStyle();
            titleStyle2.fontSize = 20;
            titleStyle2.normal.textColor = new Color(46f/256f, 163f/256f, 256f/256f, 256f/256f);
            GUI.Label(new Rect(Screen.width / 2 - 70, Screen.height / 2 -30, 100, 30), "是否覆盖已有关卡？", titleStyle2);