diff --git a/assets/index.less b/assets/index.less
index 7946275..1fac4b4 100644
--- a/assets/index.less
+++ b/assets/index.less
@@ -3,11 +3,11 @@
 .@{prefixCls} {
   &-content {
     height: 0;
-    opacity: 0;
     transition-duration: .3s;
-    transition-timing-function: ease-in;
+    // transition-timing-function: cubic-bezier(0.55, 0.055, 0.675, 0.19);
+    transition-timing-function: cubic-bezier(0.215, 0.61, 0.355, 1);
     overflow: hidden;
-    > p, > div {
+    & > &-box {
       margin-top: 16px;
       margin-bottom: 16px;
     }
diff --git a/assets/index/ant.less b/assets/index/ant.less
index f7ea494..c2c4ef3 100644
--- a/assets/index/ant.less
+++ b/assets/index/ant.less
@@ -1,5 +1,5 @@
 @prefixCls: rc-collapse;
-@borderStyle: 1px solid #d9d9d9;
+@borderStyle: 1px solid #e9e9e9;
 
 #arrow {
   .common(){
@@ -22,40 +22,54 @@
 }
 
 .@{prefixCls} {
-  background-color: #f3f5f7;
+  background-color: #fbfbfb;
   border-radius: 3px;
   border-top: @borderStyle;
   border-left: @borderStyle;
   border-right: @borderStyle;
 
-  &-header {
-    height: 38px;
-    line-height: 38px;
-    text-indent: 16px;
-    color: #666;
-    border-bottom: @borderStyle;
-    &:before {
-      display: inline-block;
-      content: '\20';
-      #arrow > .common();
-      #arrow > .right(3px, 4px, #666);
-      vertical-align: middle;
-      margin-right: 8px;
+  & > &-item {
+    > .@{prefixCls}-header {
+      height: 38px;
+      line-height: 38px;
+      text-indent: 16px;
+      color: #666;
+      border-bottom: @borderStyle;
+      &:before {
+        display: inline-block;
+        content: '\20';
+        #arrow > .common();
+        #arrow > .right(3px, 4px, #666);
+        vertical-align: middle;
+        margin-right: 8px;
+      }
     }
   }
 
   &-content {
     color: #999;
     padding: 0 16px;
-    background-color: #fbfbfb;
+    background-color: #f4f4f4;
+  }
+
+  &-item:last-child {
+    > .@{prefixCls}-content {
+      border-radius: 0 0 3px 3px;
+    }
   }
 
   &-content-active {
     border-bottom: @borderStyle;
   }
-  &-item-active {
-    .@{prefixCls}-header::before {
-      #arrow > .bottom(3px, 4px, #666);
+
+  & > &-item-active {
+    > .@{prefixCls}-header {
+      border-bottom: none;
+
+      &:before {
+        #arrow > .bottom(3px, 4px, #666);
+        margin-right: 6px;
+      }
     }
   }
 }
diff --git a/package.json b/package.json
index 7d36d7c..562bff3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "rc-collapse",
-  "version": "1.2.1",
+  "version": "1.2.2",
   "description": "rc-collapse ui component for react",
   "keywords": [
     "react",
diff --git a/src/Panel.jsx b/src/Panel.jsx
index 8a438ed..4e658ae 100644
--- a/src/Panel.jsx
+++ b/src/Panel.jsx
@@ -49,8 +49,11 @@ module.exports = createClass({
 
     return (
       <div className={itemCls}>
-        <div className={headerCls} onClick={this.handleItemClick}>{header}</div>
-        <div className={contentCls} ref="content">{children}</div>
+        <div className={headerCls} onClick={this.handleItemClick}
+          role="tab" aria-expanded={isActive}>{header}</div>
+        <div className={contentCls} ref="content" role="tabpanel">
+          <div className={`${prefixCls}-content-box`}>{children}</div>
+        </div>
       </div>
     );
   },
@@ -59,7 +62,6 @@ module.exports = createClass({
     if (this.props.isActive) {
       var el = findDOMNode(this.refs.content);
       el.style.height = 'auto';
-      el.style.opacity = 1;
     }
   },
 
@@ -81,15 +83,12 @@ module.exports = createClass({
 
     // start state
     el.style.height = opacity ? scrollHeight : 0;
-    el.style.opacity = opacity;
 
-    cssAnimation.setTransition(el, 'Property', 'height ,opacity');
+    cssAnimation.setTransition(el, 'Property', 'height');
     cssAnimation.style(el, {
-      height: opacity ? 0 : scrollHeight,
-      opacity: opacity ? 0 : 1
+      height: opacity ? 0 : scrollHeight
     }, function() {
       el.style.height = opacity ? 0 : 'auto';
-      el.style.opacity = opacity ? 0 : 1;
       cssAnimation.setTransition(el, 'Property', '');
     });
   }