Edit in JSFiddle

<h1>
Single level accordion
</h1>

<div class="accordion">
  <h2 class="accordion-header">Header 1</h2>
  <div class="accordion-content">
    Content 1 goes here. It can be anything. A list, a table, multiple paragraphs, etc. 
  </div>
  <h2 class="accordion-header">Header 2</h2>
  <div class="accordion-content">
    Content 2 goes here. It can be anything. A list, a table, multiple paragraphs, etc. 
  </div>
  <h2 class="accordion-header">Header 3</h2>
  <div class="accordion-content">
    Content 3 goes here. It can be anything. A list, a table, multiple paragraphs, etc. 
  </div>
</div>