use new index page for popup

manifest.json

@@ -12,7 +12,7 @@
 		"default_icon": {
 			"19": "icon.png"
 		},
-		"default_popup": "popup.html"
+		"default_popup": "index.html"
 	},
 
 	"background": {

stylesheets/index.css

@@ -1,3 +1,11 @@
+.clearfix:before, .clearfix:after { content: "\0020"; display: block; height: 0; overflow: hidden; }
+.clearfix:after { clear: both; }
+.clearfix { zoom: 1; }
+
+body {
+  min-width: 320px;
+  min-height: 500px;
+}
 .number.error {
   background-color: #ffdddd;
 }