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HTML

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Insecure Resource

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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 

              
                <!--
Hey! Read this first!

Just to let you know, this Pen was made in 2014!

It's been a while, and a lot has changed on the web.

As cool as this solution is, you might want to do your own
research into the accessibility of this "checkbox hack".

So take it with a pinch of salt, maybe treat it as an
object in the museum of the history of the web, and above
all else, make sure your websites are accessible!

Here's some recommended reading on the subject:

https://adrianroselli.com/2023/03/css-only-widgets-are-inaccessible.html

https://hidde.blog/dialog-modal-popover-differences/
-->

<input id="toggler" class="modal-toggler" type="checkbox" aria-hidden="true">
<section class="modal-container">
  <label for="toggler" class="modal  close-modal-area"></label>
  <div class="modal  modal-box">
    <h1>Modal Container without JS</h1>
    <label for="toggler" class="toggle-modal-button">Close</label>
  </div>
</section>
<section class="content">
  <label for="toggler" class="toggle-modal-button">Show the Modal</label>
  <p><strong>Hey! Be warned!</strong></p>
  <p>This was built in 2014 as a proof-of-concept and isn't very accessible! Seriously, try using your keyboard. This is kind of terrible, and I wish I had never made it and enabled this dark pattern to proliferate.</p>
  <p>So you probably shouldn’t use this.</p>
  <p>We can build much better and accessible interfaces with the web available to us today. Check out the <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/popover"><code>popover</code> attribute</a> or the <a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Element/dialog"><code>&lt;dialog&gt;</code> element</a>!</p>
  <p>This Pen still exists purely as an artifact from the history of the web.</p>
  <p>Read more:</p>
  <ul>
    <li><a href="https://adrianroselli.com/2023/03/css-only-widgets-are-inaccessible.html"><q>CSS-only widgets are inaccessible</q> by Adrian Roselli</a></li>
    <li><a href="https://hidde.blog/dialog-modal-popover-differences/"><q>Dialogs and popovers seem similar. How are they different?</q> by Hidde de Vries</a></li>
  </ul>
</section>
!

CSS 

              
                [aria-hidden="true"] {
  display: none;
}

.modal-container {
  background: rgba(black, 0.75);
  opacity: 0;
  color: white;
  width:  100%;
  height: 100%;
  position: fixed;
  top:  0;
  left: 0;
  visibility: hidden;
  transition: opacity  0.5s,
              visibility 0s linear 0.5s;
  z-index: 2;
  
  .modal-toggler:checked + & {
    opacity: 1;
    visibility: visible;
    transition: opacity 0.5s;
  }
}

.modal {
  position: absolute;
  top:  50%;
  left: 50%;
  padding: 2em;
  border-radius: 0.5em;
  transform: translateX(-50%) translateY(-50%);
  
  &.close-modal-area {
    width:  100%;
    height: 100%;
  }
  
  &.modal-box {
    background: black;
    text-align: center;
  }
  
  .content & {
    width: 100%;
    max-width: 40em;
  }
}

.toggle-modal-button {
  background-color: transparent;
  color: white;
  display: inline-block;
  padding: 1em;
  cursor: pointer;
  border-radius: 0.5em;
  box-shadow: inset 0 0 1px black;
  transition: background-color 0.2s,
              color            0.2s,
              transform        0.1s linear;
  
  &:hover,
  &:focus,
  &:active {
    background-color: rgba(black, 0.25);
    box-shadow: none;
    transition: background-color 0.2s,
                color            0.2s,
                box-shadow       0.2s,
                transform        0.1s linear;
  }
  
  &:active {
    transform: scale(1.2);
  }
  
  .content & {
    color: rgba(black, 0.75);
    margin-bottom: 1em;
  }
}

.content {
  color: black;
  width: 90%;
  max-width: 600px;
  padding-top: 2em;
  margin: 0 auto;
  
  & > * {
    margin-top: 1em;
  }
}


html {
  box-sizing: border-box;
}
*, *::before, *::after {
  box-sizing: inherit;
}



body {
  background-color: mistyrose;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
  font-weight: 400;
}

h1 {
  line-height: 1;
}

p {
  margin: 0;
  line-height: 2;
}
!

JS
!
999px

Console