[improvement] move overlay component (#2192)

packages/popup/index.less

@@ -1,15 +1,6 @@
 @import '../style/var';
 
 .van {
-  &-modal {
-    position: fixed;
-    width: 100%;
-    height: 100%;
-    top: 0;
-    left: 0;
-    background-color: rgba(0, 0, 0, 0.7);
-  }
-
   &-overflow-hidden {
     overflow: hidden !important;
   }

packages/popup/test/index.spec.js

@@ -114,7 +114,7 @@ test('render overlay', () => {
     }
   });
 
-  expect(div.querySelector('.van-modal')).toBeTruthy();
+  expect(div.querySelector('.van-overlay')).toBeTruthy();
 });
 
 test('close on click modal', () => {
@@ -136,7 +136,7 @@ test('close on click modal', () => {
     }
   });
 
-  const modal = div.querySelector('.van-modal');
+  const modal = div.querySelector('.van-overlay');
   triggerDrag(modal, 0, -30);
   modal.click();
   expect(wrapper.vm.value).toBeFalsy();