Use responsive design to allow your content to zoom and respond to various screen sizes.
Present content without loss of information or functionality, and without requiring scrolling in two dimensions, except for parts of the content which require two-dimensional layout for usage or meaning.
Examples of content which require two-dimensional layout are images, maps, diagrams, video, games, presentations, data tables, and interfaces where it is necessary to keep toolbars in view while manipulating content.
For a number of reasons including data persistence, performance and security, it is sometimes beneficial to terminate idle user sessions.
So that users do not lose data, it's important to warn them of a session that is about to expire and give them the option to continue. This is especially true in the case of people who might take longer to read or interact with a page due to a disability. It's important to make such prompts accessible.