Anatomy of a CSS Ruleset

The W3 describes CSS as …

a simple mechanism for adding style (e.g. fonts, colors, spacing) to Web documents.

CSS is a computer language.

1
h1 { font-size: 1.5em }

Ruleset
Declaration
Declaration Block
Property
Value
Keyword

Selectors

Selectors specify which elements are to be influenced by the style rule

https://www.w3.org/TR/selectors-3/

Properties

Values and units

More…

CSS Terms and Definitions
https://www.impressivewebs.com/css-terms-definitions/

MDN Web Docs: CSS Syntax
https://developer.mozilla.org/en-US/docs/Web/CSS/Syntax