Graphical CSS----progressive enhancement and graceful demotion

Progressive enhancement: First of all to ensure that the core of the implementation of the function, so that any bottom browser can see the site content,

Then consider the use of advanced but not necessary enhancements such as CSS and JavaScript

Graceful downgrade: Consider whether the user of the bottom device can see all the content,

Based on this, the design for high-end users, not only the high-end equipment users to provide a perfect application,

Also to design different levels of less-than-perfect applications for device users of different performance levels

Graphical CSS----progressive enhancement and graceful demotion