CSS basic data types are a kind of component value type. They define the kinds of values (keywords and units) accepted by CSS properties and functions.
Data types are denoted by a keyword placed between the inequality signs "<" and ">":
<angle>, <blend-mode>, <color>, <custom-ident>, <frequency>, <gradient>, <image>, <length>, <number>, <percentage>, <position>, <ratio>, <resolution>, <shape>, <string>, <time>, <timing-function>, <uri>