At Verko, We have provided two Under Construction Page :
You can see the v1 here -> http://dahz.daffyhazan.com/verko/under-construction-v1/
You can see the v2 here -> http://dahz.daffyhazan.com/verko/under-construction-v2/
You can use this page when you’re developing your site
1. Install this plugin : Restricted Site Access
2. Activate the plugin.
3. Go to Settings > Reading.
4. You will find new option as you can see in below screenshot :
5. Choose your under construction page from Handle restricted user dropdown list.
6. Your non-logged user will be redirected to that page, you can access entire page with login, and you can deactivate the plugin if you think your site is ready to launch.