9-extend-one-set-of-css-styles-to-another-element.html

<!-- Extend One Set of CSS Styles to Another Element
Sass has a feature called extend that makes it easy to borrow the CSS rules from one element and build upon them in another.

For example, the below block of CSS rules style a .panel class. It has a background-color, height and border.

.panel{
  background-color: red;
  height: 70px;
  border: 2px solid green;
}
Now you want another panel called .big-panel. It has the same base properties as .panel, but also needs a width and font-size. It's possible to copy and paste the initial CSS rules from .panel, but the code becomes repetitive as you add more types of panels. The extend directive is a simple way to reuse the rules written for one element, then add more for another:

.big-panel{
  @extend .panel;
  width: 150px;
  font-size: 2em;
}
The .big-panel will have the same properties as .panel in addition to the new styles.

Make a class .info-important that extends .info and also has a background-color set to magenta.

- Your info-important class should have a background-color set to magenta.
- Your info-important class should use @extend to inherit the styling from the info class.
-->
<style type='text/scss'>
  h3 {
    text-align: center;
  }

  .info {
    width: 200px;
    border: 1px solid black;
    margin: 0 auto;
  }

  .info-important {
    @extend .info;
    background-color: magenta;
  }

</style>
<h3>Posts</h3>
<div class="info-important">
    <p>This is an important post. It should extend the class ".info" and have its own CSS styles.</p>
</div>

<div class="info">
    <p>This is a simple post. It has basic styling and can be extended for other uses.</p>
</div>