样式优化：虚线样式调整

src/views/exam/components/stepItem.vue

@@ -261,7 +261,7 @@ onMounted(async () => {
     top: 0;
     left: 15.55px;
     z-index: 6;
-    height: 100%;
+    height: 480px;
     width: 0;
     border-left: 1px dashed #C0C4CC;
   }