feat: publicize doc implemetation

one/docs/demo/overlay/stack-display-order.vue

@@ -0,0 +1,84 @@
+<template>
+<article>
+  <veui-button
+    ref="a"
+    @click="aOpen = !aOpen"
+  >
+    Toggle A
+  </veui-button>
+  <veui-overlay
+    target="a"
+    position="top-start"
+    :open.sync="aOpen"
+    overlay-class="relative-overlay"
+  >
+    A
+  </veui-overlay>
+
+  <veui-button
+    ref="b"
+    @click="bOpen = !bOpen"
+  >
+    Toggle B
+  </veui-button>
+  <veui-overlay
+    target="b"
+    position="top-start"
+    :open.sync="bOpen"
+    overlay-class="relative-overlay"
+  >
+    B
+  </veui-overlay>
+
+  <veui-button
+    ref="c"
+    @click="cOpen = !cOpen"
+  >
+    Toggle C
+  </veui-button>
+  <veui-overlay
+    target="c"
+    position="top-start"
+    :open.sync="cOpen"
+    overlay-class="relative-overlay"
+  >
+    C
+  </veui-overlay>
+  <veui-button
+    ui="xs"
+    @click="aOpen = bOpen = cOpen = false"
+  >
+    Hide all
+  </veui-button>
+</article>
+</template>
+
+<script>
+import { Overlay, Button } from 'veui'
+
+export default {
+  components: {
+    'veui-overlay': Overlay,
+    'veui-button': Button
+  },
+  data () {
+    return {
+      aOpen: false,
+      bOpen: false,
+      cOpen: false
+    }
+  }
+}
+</script>
+
+<style lang="less" docs scoped>
+.veui-overlay {
+  display: none;
+}
+
+.veui-button {
+  margin-right: 10px;
+}
+</style>
+
+<style lang="less" src="./relative.less" docs></style>