Introduction

Jess has no ambient function namespace. Import the helpers you use so the stylesheet stays explicit and CSS function names remain available to the browser.

The compiler provides trusted Less and Sass function modules:

@-from "#less" import (mix);

.box {
  color: $mix(#ff0000, #0000ff, 50%);
}

You can rename an imported helper:

@-from "#less" import (rgb as jessRgb);

.color {
  color: $jessRgb(1, 2, 3);
  background-color: rgb(255 255 255 / 0.8);
}

The first call uses the explicit imported binding. The second remains a native CSS function. Imports never claim bare CSS-shaped calls.

Use @-use "#less" as less; when a namespace reads better, then call helpers as $less.mix(...). Built-in compiler modules do not require a script runtime. Local or package JavaScript and TypeScript modules require @jesscss/plugin-js. See Modules & imports for the shared Jess and Less 5 module contract.