pip style fix

packages/artplayer/src/style/mask.scss

@@ -1,6 +1,8 @@
 .artplayer-video-player {
     .artplayer-mask {
         display: none;
+        align-items: center;
+        justify-content: center;
         position: absolute;
         z-index: 50;
         left: 0;

packages/artplayer/src/style/pip.scss

@@ -54,9 +54,6 @@
         }
 
         .artplayer-mask {
-            display: flex;
-            align-items: center;
-            justify-content: center;
             .art-state {
                 position: static;
             }