JSFiddle - React, Tailwind, and code Playground

HTML

<main>
  <header>
    <h1>Site</h1>
  </header>
  
  <section>
    <article>
      <h2>Title</h2>
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Nemo molestias ex officia eligendi reiciendis fuga magnam? Ullam ut ab doloremque accusamus iusto aliquam facilis sapiente!</p>
    </article>
    <article>
      <h2>Title</h2>
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Nemo molestias ex officia eligendi reiciendis fuga magnam? Ullam ut ab doloremque accusamus iusto aliquam facilis sapiente!</p>
    </article>
  </section>
  
  <aside>
    <div class="module">
      <h3>Module</h3>
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Optio rem ab delectus fugit repellendus perspiciatis dolor consequuntur tenetur voluptatem a vitae odit aspernatur? Voluptas quisquam corporis nostrum aspernatur aliquid harum saepe ab pariatur veniam iste ipsam alias nemo voluptatibus doloribus.</p>
    </div>
  </aside>
</main>

CSS

* {
}

body {
  padding: 30px;
}

header {
  background: lightblue;
}

section {
  background: lightgreen;
  width: 75%;
  float: left;
  width: calc(75% - 1rem);

}

article {
  background: white;
}

aside {

  background: pink;
width: 25%;  
float: right;
  
}

header, article, section, .module {
  padding: 1rem;
}