counter++
counter-increment
Add 1 to a CSS counter that is declared elsewhere.
Property values
The counter-increment property is used in tandem with the counter-reset property. They both expect a counter-name, which is arbitrarily chosen.
Each element of a document that matches a selector which has a counter-increment property will cause that property-name to increase in value by 1.
Examples
/* Using a CSS counter */
h1:first-of-type {
counter-reset: C;
}
h1::before {
counter-increment: C;
content: "Section " counter(C) ":";
}