CSS: Case Sensitivity

CSS Selector for HTML tag names

Case-Insensitive

div { color: red; }
/* is same as */
DIV { color: red; }

CSS Selector for HTML attribute names

Case-Insensitive

div.abc { color: red; }
/* is same as */
div.ABC { color: red; }

CSS Selector for HTML attribute values

Case-Sensitive

• CSS: attribute selector ([x])

/* color span tag with class name starting with abc.
Case-Sensitive
*/
span[class ^="abc"]

CSS property names

CSS property names are case-insensitive.

CSS keywords

Standard keywords like none, auto, and block are case-insensitive.

CSS function names

CSS function names, like calc or rgb are case-insensitive.

At-rules

At-rules, like @media or @import, are case-insensitive.