fix: 优化样式，放大popup的窗口，消除滚动条，整体下一点点

Author: 周昊

css/app.css

@@ -1,6 +1,8 @@
+
 #container {
   width: 400px;
   height: 400px;
+  margin: 20px auto 0 ;
 }
 
 #uploader {

js/background.js

@@ -1,6 +1,6 @@
 chrome.browserAction.onClicked.addListener(function (tab) {
-    var w = 400;
-    var h = 400;
+    var w = 500;
+    var h = 450;
     var left = Math.round((screen.width / 2) - (w / 2));
     var top = Math.round((screen.height / 2) - (h / 2));
     if (!checkOptions()) {
@@ -32,4 +32,4 @@ function checkOptions() {
         }
     });
     return true;
-}
+}