diff --git a/dialog.css b/dialog.css
index 30cb212..83be4d9 100644
--- a/dialog.css
+++ b/dialog.css
@@ -1,8 +1,9 @@
 .dialog {
   position: fixed;
   top: 150px;
-  left: 5%;
-  width: 90%;
+  left: 0;
+  right: 0;
+  margin: auto;
   z-index: 1000;
   text-align: center;
 }
diff --git a/index.js b/index.js
index 3a6448b..3ec511c 100644
--- a/index.js
+++ b/index.js
@@ -248,6 +248,7 @@ Dialog.prototype.show = function(){
   // position
   document.body.appendChild(this.el);
   this._classes.remove('hide');
+  this.el.style.width = query('.content', this.el).offsetWidth+"px";
   this.emit('show');
   return this;
 };