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HTML

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CSS

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CSS Base

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JavaScript

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Babel includes JSX processing.

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HTML 

              
                <section class="products">
  <h1 class="products__heading">Products</h1>
  <ul class="products__list">
    <li class="products__item"><a href="#">Fashion</a></li>
    <li class="products__item"><a href="#">Notebooks &amp; tablets</a></li>
    <li class="products__item"><a href="#">Household electronics</a></li>
    <li class="products__item"><a href="#">Car equipment</a></li>
  </ul>  
</section>

<div class="products">
  <h1 class="products__heading">Products</h1>
  <div class="products__list">
    <p class="products__item"><a href="#">Fashion</a></p>
    <p class="products__item"><a href="#">Notebooks &amp; tablets</a></p>
    <p class="products__item"><a href="#">Household electronics</a></p>
    <p class="products__item"><a href="#">Car equipment</a></p>
  </div>  
</div>

<aside class="offers">
  <h2 class="offers__heading">Our current offer</h2>
  <div class="offers__content">
    <p class="offers__copy">
      This, of course, is not the real copy for this advertisement. The <em>real words</em> will be written once you have approved the headline.
    </p>
    <p class="offers__copy">
      Rest assured, the words will expand the concept. With clarity. Conviction. And even a little wit.
    </p>
  </div>
</aside>
!

CSS 

              
                @mixin primaryHeading() {
  font-size: 2rem;
  text-transform: uppercase;
  border-bottom: 2px solid #000000;
  margin-bottom: 1rem;
}

@mixin copy() {
  font-size: 1rem;
  line-height: 1.2;
}

@mixin box() {
  padding: 0.5rem;
  margin: 0.5rem;
}

/* the products block */
.products {
  @include box;
  background-color: #cccccc;
  &__heading {
    @include primaryHeading;
  }
  &__list {
    @include box;
  }
  &__item {
  @include copy;
  font-weight: 700;
    a{
      text-decoration: none;
      color: inherit;
        &:focus,
        &:hover {
          text-decoration: underline;
      }
    }
  }
}

/* the offers block */
.offers {
  @include box;
  background-color: #cccccc;
  &__heading {
    @include primaryHeading;
  }
  &__content {
    @include box;
  }
  &__copy {
    @include copy;
  }
}
!

JS
!
999px

Console