提交初始版本，使用vant ui库

miniprogram_npm/@vant/weapp/nav-bar/index.wxs

@@ -0,0 +1,13 @@
+/* eslint-disable */
+var style = require('../wxs/style.wxs');
+
+function barStyle(data) {
+  return style({
+    'z-index': data.zIndex,
+    'padding-top': data.safeAreaInsetTop ? data.statusBarHeight + 'px' : 0,
+  });
+}
+
+module.exports = {
+  barStyle: barStyle,
+};