nav 结构+样式
1. 样式一
预览地址 https://emloxe.github.io/xydaily-component/nav/nav1.html
代码地址 https://github.com/emloxe/xydaily-component/blob/master/nav/nav1.html
2. 样式二
预览地址 https://emloxe.github.io/xydaily-component/nav/nav2.html
代码地址 https://github.com/emloxe/xydaily-component/blob/master/nav/nav2.html
3. 样式三
预览地址 https://emloxe.github.io/xydaily-component/nav/nav3.html
代码地址 https://github.com/emloxe/xydaily-component/blob/master/nav/nav3.html