change .yoho-tip@z-index to 100

@@ -111,7 +111,7 @@ button {
     color: #fff;
     font-size: 18PX;
     border: none;
-    z-index: 4;
+    z-index: 100;
     box-sizing: border-box;
     border-radius: 10PX;
 }