<main class="content">
  <div class="container">
    <div class="items">
      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
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      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
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      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
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      <div class="item"></div>
      <div class="item"></div>
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      <div class="item"></div>
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      <div class="item"></div>
      <div class="item"></div>
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      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
      <div class="item"></div>
    </div>
  </div>
</main>
* {
  box-sizing: border-box;
}

.container {
  max-width: 800px;
  width: 100%;
  margin: 0 auto;
  padding: 0 20px;
}

.items {
  display: grid;
  grid-template-columns: repeat(18, 1fr );
  gap: 10px;
}
.item {
  outline: 1px solid green;
  min-height: 100px;
}

External CSS

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External JavaScript

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