fix filter-nav

@@ -66,6 +66,30 @@ body {
     color: #999;
 }
 
+.filter-nav li > a{
+    position: relative;
+}
+
+.filter-nav .icon {
+    position: absolute;
+    top: 0;
+    bottom: 0;
+    left: 100%;
+
+    .up, .down {
+        position: absolute;
+    }
+
+    .up {
+        transform: translateY(-6px);
+    }
+
+    .down {
+        transform: translateY(6px);
+    }
+}
+
+
 .filter-nav .iconfont.cur {
     color: inherit;
 }