How to get selector properties into a variable in sass/scss?

Question

Sass

Hello.
Given:
.demo{ color: red }
How do I get the .demo properties into the $test variable?

Answer 1

Usually used for these purposes @extend:
https://sass-scss.ru/guide/

.message {
  border: 1px solid #ccc;
  padding: 10px;
  color: #333;
}
.success {
  @extend .message;
  border-color: green;
}
.error {
  @extend .message;
  border-color: red;
}
.warning {
  @extend .message;
  border-color: yellow;
}

Answer 2

No way