The growth of the mobile Web requires you to have the page layout adopted for mobile devices like tablets and smart phones.
What is the Responsive Web Design? See Wikipedia...

 You should have flexible website that fits on any device, rather than having to create and maintain separate versions for each device.

A responsive website creates version of the same website that can stretch and resize with the browser.
When you get to a specific width, the website can snap to a different layout specifically for mobile devices.
The benefits are obvious: You build a website once, and it works seamlessly across thousands of different screens.

List of Websites

• The Holy Trinity Store
• AtlasPhones.com