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About the <head>

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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 

              
                <div class="wrapper">
  <header>
    <h2>SingleBox</h2>
    <nav>
      <ul>
        <li>
          <a href="#">Design</a>
        </li>
        <li>
          <a href="#">Code</a>
        </li>
        <li>
          <a href="#">Research</a>
        </li>
      </ul>
    </nav>
  </header>
  <div class="grid-12">
    <div class="article">
      <p>
        Lacinia eget tellus sociis mi ultrices urna diam. Ipsum libero, curabitur aenean leo, dui lacus, tortor ultrices faucibus. Commodo rhoncus sagittis ut tellus rhoncus non nec in viverra. Sit urna eu viverra fermentum hac velit consequat, sagittis accumsan. Pellentesque amet vel, bibendum tortor.
      </p>
      <p>
        <img src="https://source.unsplash.com/700x380/" />
      </p>
      <p>
        Lacinia eget tellus sociis mi ultrices urna diam. Ipsum libero, curabitur aenean leo, dui lacus, tortor ultrices faucibus. Commodo rhoncus sagittis ut tellus rhoncus non nec in viverra. Sit urna eu viverra fermentum hac velit consequat, sagittis accumsan. Pellentesque amet vel, bibendum tortor.
      </p>
    </div>
    <!-- .article -->
    
    <aside class="sidebar">
      <h3>Recent comments</h3>
      <div class="comment">
        <div class="comment__avatar">
          <img src="http://source.unsplash.com/100x100/?portrait" />
        </div>
        <!-- .comment__avatar -->
        <div class="comment__content">
          <div class="comment__content__wrap">
            <div class="comment__content__top">
              <h5 class="comment__content__title">Kuncung</h5>
              <div class="comment__content__time">Yesterday</div>
            </div>
            <!-- .comment__content__top -->
            <p>Vel purus sit tellus morbi at nisl, interdum cursus vestibulum. Eleifend id ut elementum diam arcu elit faucibus dictum eu.</p>
          </div>
          <!-- .comment__wrap -->
        </div>
        <!-- .comment__content -->
      </div>
      <!-- .comment -->
      
      <div class="comment">
        <div class="comment__avatar">
          <img src="http://source.unsplash.com/100x100/?portrait,girl" />
        </div>
        <!-- .comment__avatar -->
        <div class="comment__content">
          <div class="comment__content__wrap">
            <div class="comment__content__top">
              <h5 class="comment__content__title">John</h5>
              <div class="comment__content__time">Feb 2nd, 2020</div>
            </div>
            <!-- .comment__content__top -->
            <p>Vel purus sit tellus morbi at nisl, interdum cursus vestibulum. Eleifend id ut elementum diam arcu elit faucibus dictum eu.</p>
          </div>
          <!-- .comment__wrap -->
        </div>
        <!-- .comment__content -->
      </div>
      <!-- .comment -->
      
      <div class="comment">
        <div class="comment__avatar">
          <img src="http://source.unsplash.com/100x100/?portrait,man" />
        </div>
        <!-- .comment__avatar -->
        <div class="comment__content">
          <div class="comment__content__wrap">
            <div class="comment__content__top">
              <h5 class="comment__content__title">Lucas</h5>
              <div class="comment__content__time">Feb 1st, 2020</div>
            </div>
            <!-- .comment__content__top -->
            <p>Vel purus sit tellus morbi at nisl, interdum cursus vestibulum. Eleifend id ut elementum diam arcu elit faucibus dictum eu.</p>
          </div>
          <!-- .comment__wrap -->
        </div>
        <!-- .comment__content -->
      </div>
      <!-- .comment -->
    </aside>
    <!-- .sidebar -->
  </div>
  <!-- .grid-12 -->
</div>
!

CSS 

              
                :root{
  --f-primary: 'Sarabun', sans-serif;
  --f-secondary: 'Abril Fatface', cursive;
  --c-primary: #081484;
}

body{
  font-family: var(--f-primary);
  background-color: #fafafa;
}

.wrapper{
  max-width: 1140px;
  margin-left: auto;
  margin-right: auto;
}
h2{
  font-family: var(--f-secondary);
  font-weight: normal;
  color: var(--c-primary);
}
p{
  font-size: 1.125em;
  line-height: 1.5;
  color: rgba(black, 0.85);
  margin: 1.5rem 0; 
}
img{
  max-width: 100%;
}

.grid-12{
  height: 500px;
  display: grid;
  
  //-------------------------
  // 12 is total columns
  // 1fr: flexible length which represents a fraction of the leftover space in the grid container
  // Source: https://www.w3.org/TR/css3-grid-layout/#fr-unit
  //--------------------------
  grid-template-columns: repeat(12, 1fr);
  
  // --------------------------
  // 1.5rem = 24px for gutter.
  // --------------------------
  grid-gap: 1.5rem;
}

header{
  grid-column: span 12;
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
}
nav{
  ul{
    list-style: none;
    display: inline-flex;
    padding: 0;
    margin: 0;
  }
  li{
    margin-right: 4.5rem;
    &:last-child{
      margin-right: 0;
    }
    a{
      font-size: 0.875em;
      text-transform: uppercase;
      font-weight: 600;
      text-decoration: none;
      color: rgba(black, 0.5);
      letter-spacing: 1px;
      &:hover{
        color: black;
      }
    }
  }
}

.article{
  grid-column: span 6;
}
.sidebar{
  grid-column:  8 / span 5;
  h3{
    grid-column: span 4;
    font-size: 0.875em;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 500;
    margin-bottom: 2rem;
  }
}
.comment{
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 1.5rem;
  margin-bottom: 1.5rem;
  p{
    font-size: 0.875em;
    margin: 0.5rem 0;
    opacity: 0.7;
    &:last-child{
      margin-bottom: 0;
    }
  }
  &__avatar{
    grid-column: span 1; 
    img{
      max-width: calc(100% - 16px);
      border-radius: 100%;
      border: 8px solid white;
    }
  }
  &__content{
    grid-column: span 3;
    &__wrap{
      background-color: white;
      border: 1px solid rgba(black, 0.1);
      border-radius: 5px;
      padding: 1rem;
    }
    &__top{
      display: flex;
      justify-content: space-between;
      align-items: center;
      h5{
        font-size: 1em;
        font-weight: 500;
      }
    }
    &__title{
      margin: 0;
    }
    &__time{
      font-size: 0.875em;
      color: rgba(black, 0.5);
    }
  }
}
!

JS
!
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