The syntax of <dashed-ident> is similar to CSS identifiers (such as property names), except that it is case-sensitive. It starts with two dashes, followed by the user-defined identifier.

The double dash at the beginning makes them easily identifiable when reading through a CSS code block.

Just like <custom-ident> <dashed-ident>s are defined by the user, but unlike <custom-ident> CSS will never define a <dashed-ident>.

When <dashed-ident> is used with CSS custom properties, the property is declared first and then used within a CSS var() function.

html {
  --primary-color: red;
  --secondary-color: blue;
  --tertiary-color: green;
}

h1,
h4 {
  color: var(--primary-color);
}

h2,
h5 {
  color: var(--secondary-color);
}

h3,
h6 {
  color: var(--tertiary-color);
}

When <dashed-ident> is used with the @color-profile at-rule, the at-rule is declared first and then used within a CSS color() function.

@color-profile --my-color-profile {
  src: url("https://example.org/SWOP2006_Coated5v2.icc");
}

.header {
  background-color: color(--my-color-profile 0% 70% 20% 0%);
}

When <dashed-ident> is used with the @font-palette-values at-rule, the at-rule is declared first and then used as the value for the font-palette property.

@font-palette-values --my-palette {
  font-family: Bixa;
  base-palette: 1;
  override-colors: 0 #ff0000;
}

h1,
h2,
h3,
h4 {
  font-palette: --my-palette;
}

• <ident>
• <custom-ident>