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HTML

              
                <div class="wrapper">
  <ul class="Accordion">
    <li>
      <input type="checkbox" id="ac1">
      <label for="ac1">Accordion 1</label>
      <div class="content">
        <p>Id diam vel quam elementum pulvinar. Feugiat nibh sed pulvinar proin gravida hendrerit lectus a.</p>
      </div>
    </li>
    <li>
      <input type="checkbox" id="ac2">
      <label for="ac2">Accordion 2</label>
      <div class="content">
        <p>Elit pellentesque habitant morbi tristique senectus et netus. Interdum posuere lorem ipsum dolor sit amet consectetur. Malesuada nunc vel risus commodo viverra maecenas accumsan lacus vel. Blandit volutpat maecenas volutpat blandit aliquam. Donec adipiscing tristique risus nec feugiat in fermentum posuere. Scelerisque eleifend donec pretium vulputate. Urna neque viverra justo nec ultrices dui sapien eget mi. Odio tempor orci dapibus ultrices. Id velit ut tortor pretium viverra suspendisse potenti nullam. Convallis tellus id interdum velit laoreet. Facilisi morbi tempus iaculis urna id volutpat lacus laoreet. Sagittis eu volutpat odio facilisis mauris sit amet. Scelerisque mauris pellentesque pulvinar pellentesque habitant morbi. Cum sociis natoque penatibus et magnis dis parturient montes. Nunc congue nisi vitae suscipit tellus mauris a.</p>
      </div>
    </li>
    <li>
      <input type="checkbox" id="ac3">
      <label for="ac3">Accordion 3</label>
      <div class="content">
        <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Turpis egestas pretium aenean pharetra magna. Nisl tincidunt eget nullam non nisi est sit. Gravida in fermentum et sollicitudin ac orci phasellus egestas tellus.</p>
      </div>
    </li>
    <li>
      <input type="checkbox" id="ac4">
      <label for="ac4">Accordion 4</label>
      <div class="content">
        <p>Viverra ipsum nunc aliquet bibendum enim. Sed elementum tempus egestas sed sed risus pretium quam vulputate. Suscipit tellus mauris a diam maecenas sed enim.</p>
      </div>
    </li>
  </ul>
  <ul class="Accordion">
    <li>
      <!-- For radio buttons, remember to add a name so we switch radio instead of checking more! -->
      <input type="radio" id="acr1" name="acGroup" checked="checked">
      <label for="acr1">Accordion 1</label>
      <div class="content">
        <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Turpis egestas pretium aenean pharetra magna. Nisl tincidunt eget nullam non nisi est sit. Gravida in fermentum et sollicitudin ac orci phasellus egestas tellus.</p>
      </div>
    </li>
    <li>
      <input type="radio" id="acr2" name="acGroup">
      <label for="acr2">Accordion 2</label>
      <div class="content">
        <p>Viverra ipsum nunc aliquet bibendum enim. Sed elementum tempus egestas sed sed risus pretium quam vulputate. Suscipit tellus mauris a diam maecenas sed enim.</p>
      </div>
    </li>
    <li>
      <input type="radio" id="acr3" name="acGroup">
      <label for="acr3">Accordion 3</label>
      <div class="content">
        <p>Elit pellentesque habitant morbi tristique senectus et netus. Interdum posuere lorem ipsum dolor sit amet consectetur. Malesuada nunc vel risus commodo viverra maecenas accumsan lacus vel. Blandit volutpat maecenas volutpat blandit aliquam. Donec adipiscing tristique risus nec feugiat in fermentum posuere. Scelerisque eleifend donec pretium vulputate. Urna neque viverra justo nec ultrices dui sapien eget mi. Odio tempor orci dapibus ultrices. Id velit ut tortor pretium viverra suspendisse potenti nullam. Convallis tellus id interdum velit laoreet. Facilisi morbi tempus iaculis urna id volutpat lacus laoreet. Sagittis eu volutpat odio facilisis mauris sit amet. Scelerisque mauris pellentesque pulvinar pellentesque habitant morbi. Cum sociis natoque penatibus et magnis dis parturient montes. Nunc congue nisi vitae suscipit tellus mauris a.</p>
      </div>
    </li>
    <li>
      <input type="radio" id="acr4" name="acGroup">
      <label for="acr4">Accordion 4</label>
      <div class="content">
        <p>Id diam vel quam elementum pulvinar. Feugiat nibh sed pulvinar proin gravida hendrerit lectus a.</p>
      </div>
    </li>
  </ul>
</div>
              
            
!

CSS

              
                // Just the wrapper css, no one cares about this.
.wrapper {
  display: flex;
  gap: 20px;
  padding: 20px;
}

// Accordion css. Purposely minimal styling to show the technique instead
.Accordion {
  list-style: none;
  margin: 0;
  padding: 0;
  
  li {
    border-top: 1px solid #000;
    
    &:last-child {
      border-bottom: 1px solid #000;
    }
  }
  
  input { // let's hide the input, it's just used to check if we want the accordion open or not
    height: 0;
    width: 0;
    visibility: hidden;
    opacity: 0;
    position: absolute;
  }
  
  label { // base styling of the accordion toggle
    display: block;
    padding: 8px 16px;
    cursor: pointer;
    position: relative;
    
    // This is to add the handle icon
    &::before, &::after{
      background: #000;
      content: "";
      height: 2px;
      right: 16px;
      position: absolute;
      top: 50%;
      transition: transform .5s ease;
      width: 8px;
    }
    &::before{
      transform: rotate(45deg);
      right: 21px;
    }
    &::after{
      transform: rotate(-45deg);
    }
  }
  
  input:checked + label {
    // we'll just flip the values of rotate...
    &::before{
      transform: rotate(-45deg);
    }
    &::after{
      transform: rotate(45deg);
    }
  }
  
  label + .content { // this is the closed content
    max-height: 0;
    transition: max-height .3s ease-in-out;
    overflow: hidden;
    box-sizing: border-box;
    
    p {
      margin: 0 16px 16px;
    }
  }
  
  input:checked + label + .content { // this is the open content
    max-height: var(--accordion-max-height, 999px); // set it to our local variable, or fallback to good ole 999px...
  }
}
              
            
!

JS

              
                /*
  We'll run a small script on page load to set the height of
  all the accordion items content, and store it as a css
  variable. If you have images or other things inside of the
  accordions, you might want to wait for an event that loads
  the images etc as well to get the correct height on them.
*/

const accordionContents = document.querySelectorAll(`.Accordion .content`);
[...accordionContents].forEach(el => {
  el.style.setProperty(`--accordion-max-height`, `${el.scrollHeight}px`);
});
              
            
!
999px

Console