feat: add dropdown component (currently not use)

src/components/app/AppDropdown.vue

@@ -0,0 +1,73 @@
+<script setup lang="ts">
+import { onUnmounted } from 'vue';
+import { onMounted } from 'vue';
+import { ref } from 'vue';
+
+const open = ref(false);
+const element = ref<HTMLElement>();
+
+function click({ target }: MouseEvent) {
+  if (!open.value) return;
+  if (target instanceof HTMLElement && element.value?.contains(target)) {
+    return;
+  }
+  open.value = false;
+}
+
+onMounted(() => {
+  window.addEventListener('mouseup', click);
+});
+
+onUnmounted(() => {
+  window.removeEventListener('mouseup', click);
+});
+</script>
+
+<template>
+  <div class="dropdown" ref="element">
+    <button class="dropdown__trigger" @click.stop="open = !open">
+      <slot name="trigger" />
+    </button>
+    <Transition>
+      <div class="dropdown__content" v-if="open">
+        <slot name="content" />
+      </div>
+    </Transition>
+  </div>
+</template>
+
+<style scoped>
+.dropdown {
+  display: inline-block;
+  overflow: visible;
+  position: relative;
+
+  & .dropdown__trigger {
+    appearance: none;
+    background: transparent;
+    outline: none;
+    border: none;
+    padding: 0;
+  }
+
+  & .dropdown__content {
+    position: absolute;
+    z-index: 9999;
+    top: 100%;
+    left: 0%;
+    margin-top: 0.25rem;
+    border: 1px solid var(--border-color);
+    border-radius: var(--radius-2, 7px);
+  }
+}
+
+.v-enter-active,
+.v-leave-active {
+  transition: opacity 0.15s ease;
+}
+
+.v-enter-from,
+.v-leave-to {
+  opacity: 0;
+}
+</style>