Fix nested Tabs style, close #4317

components/tabs/style/index.less

@@ -190,28 +190,28 @@
   }
 
   &:not(&-vertical) {
-    .@{tab-prefix-cls}-content {
+    > .@{tab-prefix-cls}-content {
       width: 100%;
-    }
-    .@{tab-prefix-cls}-content-animated {
-      display: flex;
-      flex-direction: row;
-      will-change: margin-left;
-      transition: margin-left 0.3s @ease-in-out;
-    }
 
-    .@{tab-prefix-cls}-tabpane {
+      > .@{tab-prefix-cls}-tabpane {
         flex-shrink: 0;
         width: 100%;
         transition: opacity 0.3s;
         opacity: 1;
       }
 
-    .@{tab-prefix-cls}-tabpane-inactive {
+      > .@{tab-prefix-cls}-tabpane-inactive {
         opacity: 0;
         height: 0;
       }
     }
+    > .@{tab-prefix-cls}-content-animated {
+      display: flex;
+      flex-direction: row;
+      will-change: margin-left;
+      transition: margin-left 0.3s @ease-in-out;
+    }
+  }
 
   &-vertical {
     > .@{tab-prefix-cls}-bar {
@@ -394,8 +394,8 @@
 .no-flex,
 .@{tab-prefix-cls}-no-animation,
 .@{tab-prefix-cls}-vertical {
-  .@{tab-prefix-cls}-content {
-    &-animated {
+  > .@{tab-prefix-cls}-content {
+    > &-animated {
       transform: none!important;
     }