# EXTEND/INHERITANCE

This is one of the most useful features of Sass. Using `@extend` lets you share a set of CSS properties from one selector to another. It helps keep your Sass very DRY. In our example we're going to create a simple series of messaging for errors, warnings and successes.

```scss
.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;
}
```

What the above code does is allow you to take the CSS properties in `.message` and apply them to `.success`, `.error`, & `.warning`. The magic happens with the generated CSS, and this helps you avoid having to write multiple class names on HTML elements. This is what it looks like:

```css
.message, .success, .error, .warning {
  border: 1px solid #cccccc;
  padding: 10px;
  color: #333;
}

.success {
  border-color: green;
}

.error {
  border-color: red;
}

.warning {
  border-color: yellow;
}
```

# EXERCISE

Write a rule for the selector `.push-button` with a `background-color: blue`, and a rule for the selector `.main-button` so that it extends `.push-button`, and also sets the `font-weight: bold`.