Stylelint within Precss

[illycz]

There are many warnings if I try use variable:

/*
 The default CSS file.

 You can use @import here to include CSS inside folders
*/
@import 'imports/reset.css';

$bg: #f00;

body {
  background-color: $bg;
  font-family: sans-serif;
  font-size: 1em;
}

Unexpected " " (selector-descendant-combinator-no-non-space)
Expected no more than 0 empty lines (selector-max-empty-lines)
Unexpected unknown type selector "$bg" (selector-type-no-unknown)