fix tabs style

components/tabs/demo/slide.md

@@ -20,6 +20,9 @@ React.render(
     <TabPane tab="tab 4" key="4">选项卡四</TabPane>
     <TabPane tab="tab 5" key="5">选项卡五</TabPane>
     <TabPane tab="tab 6" key="6">选项卡六</TabPane>
+    <TabPane tab="tab 7" key="7">选项卡七</TabPane>
+    <TabPane tab="tab 8" key="8">选项卡八</TabPane>
+    <TabPane tab="tab 9" key="9">选项卡九</TabPane>
   </Tabs>
 , document.getElementById('components-tabs-demo-slide'));
 ````

style/components/tabs.less

@@ -45,8 +45,9 @@
   &-tab-prev, &-tab-next {
     user-select: none;
     -webkit-user-select: none;
-    z-index: 1;
+    z-index: 2;
     margin-right: -2px;
+    margin-top: 1px;
     width: 32px;
     height: 100%;
     line-height: 32px;
@@ -60,7 +61,7 @@
       position: relative;
       display: inline-block;
       font-style: normal;
-      font-weight: normal;
+      font-weight: bold;
       font-variant: normal;
       line-height: inherit;
       vertical-align: baseline;
@@ -73,6 +74,10 @@
         font-family: "anticon" !important;
       }
     }
+
+    &:hover {
+      color: fadeout(#2db7f5, 20%);
+    }
   }
 
   &-tab-next {
@@ -85,6 +90,7 @@
 
   &-tab-prev {
     left: 0;
+    background: #fff;
     transform: rotate(180deg);
     filter: progid:DXImageTransform.Microsoft.BasicImage(rotation=2);
     &-icon:before {