Generated by SassMeister.com.

input.scss

@mixin dark-mode {
  :global(html[data-theme='system']) {
    @media (prefers-color-scheme: dark) {
      @content;
    }
  }

  :global(html[data-theme='dark']) {
    @content;
  }
}

$blue-300: #437ae0;
$blue-500: #1f51af;

.CurrentMethod {
  background-color: $blue-500;
}

@include dark-mode {
  .CurrentMethod {
      background-color: $blue-300;
  }
}

output.css

.CurrentMethod {
  background-color: #1f51af;
}

@media (prefers-color-scheme: dark) {
  :global(html[data-theme="system"]) .CurrentMethod {
    background-color: #437ae0;
  }
}

:global(html[data-theme="dark"]) .CurrentMethod {
  background-color: #437ae0;
}

settings.json

{
  "sass": {
    "compiler": "dart-sass/1.32.12",
    "extensions": {},
    "syntax": "SCSS",
    "outputStyle": "expanded"
  },
  "autoprefixer": false
}