vue3 모달창 트랜지션

<template>
    <transition appear name="modal">
        <div class="modal-mask">
            <div class="modal-wrapper">
              <div class="modal-container">

                <!-- Modal Header -->
                <div class="modal-header">
                  <slot name="header">
                      default header
                  </slot>
                </div>

                <!-- Modal Body -->
                <div class="modal-body">
                  <slot name="body">
                      default body
                  </slot>
                </div>

                <!-- Modal footer -->
                <!-- <div class="modal-footer">
                  <slot name="footer">
                      default footer
                      <button class="modal-default-button" @click="$emit('close')">
                        OK
                      </button>
                  </slot>
                </div> -->
              </div>
            </div>
        </div>
    </transition>
</template>

<style scoped>
.modal-mask {
  position: fixed;
  z-index: 9998;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  display: table;
  transition: opacity 0.3s ease;
}

.modal-wrapper {
  display: table-cell;
  vertical-align: middle;
}

.modal-container {
  width: 300px;
  margin: 0px auto;
  padding: 20px 30px;
  background-color: #fff;
  border-radius: 2px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.33);
  transition: all 0.3s ease;
  font-family: Helvetica, Arial, sans-serif;
}

.modal-header {
  margin-top: 0;
  color: #42b983;
}

.modal-body {
  margin: 20px 0;
}

.modal-default-button {
  float: right;
}

.modal-enter-from {
  opacity: 0;
}

.modal-leave-active {
  opacity: 0;
}

.modal-enter-from .modal-container,
.modal-leave-active .modal-container {
  -webkit-transform: scale(1.1);
  transform: scale(1.1);
}
</style>

vue3인데 모달창 띄울 때 애니매이션 효과가 잘 작동하는데 왜 닫을 때는 작동을 안하는 지 잘 모르겠어요

<AlertModal v-if="showModal" @close="showModal = false">
            <!--
            you can use custom content here to overwrite
            default content
            -->
            <template v-slot:header>
                <h3>경고! <span class="closeModalBtn" @click="showModal = false">x</span></h3>
            </template>
            <template v-slot:body>
                아무것도 입력하지 않으셨습니다.
            </template>
            <!-- <template v-slot:footer>
                copy right
            </template> -->
</AlertModal>

참고로 vue3에서는 slot을 template 태그 안에 v-slot으로 적어야 한다해서 이렇게 작성했어요

<AlertModal v-show="showModal" @close="showModal = false">
   <!-- 모달 콘텐츠 -->
</AlertModal>

.modal-enter-active,
.modal-leave-active {
  transition: opacity 0.3s ease;
}
.modal-enter, .modal-leave-to /* .modal-leave-active in <2.1.8 */ {
  opacity: 0;
  transform: scale(1.1);
}