优化demo

docs/assets/example/playlist.js

@@ -12,9 +12,6 @@ var art = new Artplayer({
             click: () => {
                 art.plugins.artplayerPluginPlaylist.show();
             },
-            style: {
-                marginRight: '15px',
-            },
         },
         {
             name: 'prev',
@@ -23,9 +20,6 @@ var art = new Artplayer({
             click: () => {
                 art.plugins.artplayerPluginPlaylist.prev();
             },
-            style: {
-                marginRight: '15px',
-            },
         },
         {
             name: 'next',