bug fix

src/views/gui/QuestionPositionTip.vue

@@ -172,6 +172,7 @@ export default {
     position: absolute;
     left: 50%;
     top: 50%;
+    transform: translate(-50%, -50%);
     background-image: url(@/assets/images/quiz-position-tip-bg.png);
     background-size: contain;
     background-repeat: no-repeat;