[bugfix] Popup: update overlay style & class (#349)

* fix: Tabbar icon line-height

* [new feature] progress add showPivot prop

* [new feature] TabItem support vue-router

* [new feature] update document header style

* [Doc] add toast english ducoment

* [bugfix] Search box-sizing wrong

* [Doc] update vant-demo respo

* [Doc] translate theme & demo pages

* [Doc] add Internationalization document

* [bugfix] remove unnecessary props

* [fix] optimize clickoutside

* [new feature] optimize find-parent

* [new feature]: change document title accordinng to language

* [new feature] Pagination code review

* [improvement] adjust icon-font unicode

* [improvement] Icon spinner color inherit

* [improvement] icon default width

* [bugfix] DateTimePicker validate date props

* [bugfix] Tab item text ellipsis

* [improvement] optimize single line ellipsis

* [Improvement] optimzie staticClass

* [Improvement] Button: use sfc instread of jsx

* [Improvement] update actionsheet close icon style

* fix: yarn.lock

* fix: icon test cases

* [bugfix] errors during ssr

* [Improvement] SubmitBar add left slot

* [new feature] ImagePreview support manually close

* fix: ImagePreview test case

* [Doc] add switch lang button in mobile

* [bugfix] Popup overlay style update

packages/mixins/popup/Modal.vue

@@ -0,0 +1,30 @@
+<template>
+  <div
+    class="van-modal"
+    :class="className"
+    :style="style"
+    @touchmove.prevent.stop
+    @click="$emit('click', $event)"
+  />
+</template>
+
+<script>
+export default {
+  name: 'van-modal',
+
+  props: {
+    zIndex: Number,
+    className: String,
+    customStyle: Object,
+  },
+
+  computed: {
+    style() {
+      return {
+        zIndex: this.zIndex,
+        ...this.customStyle
+      }
+    }
+  }
+};
+</script>