fediversity.eu/node_modules/postcss-nested/README.md

PostCSS Nested

PostCSS plugin to unwrap nested rules closer to Sass syntax.

.phone {
    &_title {
        width: 500px;
        @media (max-width: 500px) {
            width: auto;
        }
        body.is_dark & {
            color: white;
        }
    }
    img {
        display: block;
    }
}

.title {
  font-size: var(--font);

  @at-root html {
      --font: 16px
  }
}

will be processed to:

.phone_title {
    width: 500px;
}
@media (max-width: 500px) {
    .phone_title {
        width: auto;
    }
}
body.is_dark .phone_title {
    color: white;
}
.phone img {
    display: block;
}

.title {
  font-size: var(--font);
}
html {
  --font: 16px
}

Related plugins:

• Use postcss-current-selector after this plugin if you want to use current selector in properties or variables values.
• Use postcss-nested-ancestors before this plugin if you want to reference any ancestor element directly in your selectors with ^&.

Alternatives:

• See also postcss-nesting, which implements CSSWG draft.
• postcss-nested-props for nested properties like font-size.

Docs

Read full docs here.