When doing a switching transition on vue2.0, I found that the switching display was normal, but there was a delay when the switching disappeared and there was no transition effect

.detail position fixed z-index 100 top 0 left 0 width 100% height 100% overflow auto background rgba(7,17,27,.8) &.fade-enter-active,&.fade-leave-active transition opacity 3s &.fade-enter,&fade-leave-active opacity 0