You can group styles common to different rules into their own classes to save repeating yourself. CSS2-compliant browsers can reference multiple classes within individual elements.
CSS: Group Selectors and Declarations
By combining the grouping of selectors that share the same declaration and declarations that share the same selector you can apply multiple declarations to multiple selectors. This technique allows you to create compact yet powerful CSS rules. This tip combines Group Selectors with Group Declarations into one powerful technique.
CSS: Group Declarations
CSS allows you to group multiple declarations for the same selector into one rule set, separated by semicolons. This allows you to apply multiple declarations to one selector to save space.
CSS: Group Selectors
CSS allows you to group multiple selectors that share the same declaration. This optimization technique allows you to apply the same style to multiple elements to save space.
CSS: Use Shorthand Properties
Shorthand properties allow you to specify a set of related CSS properties with a single property. They combine related properties into a shorthand form. In most cases, the browser sets a default value if you leave out an optional one. There are six shorthand properties in CSS: