CSS-OM is like DOM, but for style sheets
Access to rules, properties, values, modules, etc. from within a program
Insert rules, change values, remove properties,...
"Smart" functions: you can set a value in cm and query it in inch, etc.
Same functions for property declarations in a style sheet and for property
declarations on an HTML/XML element (STYLE attribute)
There are some CSS-specific APIs and some generic ones, on which to build
for other style languages.