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HTML 

              
                <!-- Some Page Content -->
<main>
  <h1>Dialog Demo</h1>
  <h2>Scroll to open dialog.</h2>
  <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Architecto recusandae amet, rerum quasi quaerat ipsum nam earum vitae distinctio deleniti. Rerum earum excepturi ab, totam tenetur fuga praesentium illum repudiandae.</p>
  <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Architecto recusandae amet, rerum quasi quaerat ipsum nam earum vitae distinctio deleniti. Rerum earum excepturi ab, totam tenetur fuga praesentium illum repudiandae.</p>
  <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Architecto recusandae amet, rerum quasi quaerat ipsum nam earum vitae distinctio deleniti. Rerum earum excepturi ab, totam tenetur fuga praesentium illum repudiandae.</p>
  <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Architecto recusandae amet, rerum quasi quaerat ipsum nam earum vitae distinctio deleniti. Rerum earum excepturi ab, totam tenetur fuga praesentium illum repudiandae.</p>
  <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Architecto recusandae amet, rerum quasi quaerat ipsum nam earum vitae distinctio deleniti. Rerum earum excepturi ab, totam tenetur fuga praesentium illum repudiandae.</p>
  <p>Lorem ipsum dolor sit amet consectetur adipisicing elit. Architecto recusandae amet, rerum quasi quaerat ipsum nam earum vitae distinctio deleniti. Rerum earum excepturi ab, totam tenetur fuga praesentium illum repudiandae.</p>
  
  
  <!-- Dialog Button -->
  <button onclick="window.dialog.showModal();">Open Dialog</button>
</main>

<!-- Dialog Popup Itself -->
<dialog id="dialog">
  <h2>Hello.</h2>
  <p>I'm a dialog element that is open. You can close me by clicking on the "x" which is my close button. I am also styled in CSS, and can accept arbitrary content. I will remain fixed to the center of the window by default as you scroll the page.</p>
  <p>I also have a <code>::backdrop</code> you can style, which lives between me and the page.</p>
  <button onclick="window.dialog.close();" aria-label="close" class="x">❌</button>
</dialog>
!

CSS 

              
                :root {
  --page-accent: rgb(241, 212, 252);
}

// Style backdrop of dialog

dialog::backdrop {
  background: linear-gradient(
    to top,
    rgba(200, 210, 250, 0.8),
    rgba(10, 150, 130, 0.8),
  )
}

// Style dialog itself
dialog {
  padding: 1rem 3rem;
  background: var(--page-accent);
  max-width: 64ch;
}

// Style dialog button
.x {
  filter: grayscale(1);
  border: none;
  background: none;
  position: absolute;
  top: 0;
  right: 0.4rem;
}

// Additional page styling

body {
  font-family: system-ui, serif;
  line-height: 1.5;
  padding-bottom: 2rem;
}

main {
  max-width: 500px;
  margin: 0 auto;
  display: grid;
}

button {
  padding: 0.5rem;
  font-size: 1rem;
  background: var(--page-accent);
  border: 2px solid;
  border-radius: 0.5rem;
  justify-self: end;
}
!

JS
!
999px

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