A modal dialog is a dialog that appears on top of the main content and moves the system into a special mode requiring user interaction

Click on the button below to toggle the modal dialog.


The modal dialog is wrapped in a unique container with both id and data-modal attributes specified.

<div id="modal" data-modal>

  <!-- Modal  -->
  <div id="dialog" data-modal-dialog role="dialog" aria-modal="true" aria-labelledby="dialog-title" tabindex="-1">
    <h3 id="dialog-title">Modal title</h3>
    <p>This is the modal content.</p>
    <a href="#" data-modal-close>
      <svg xmlns="" width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="feather feather-x"><line x1="18" y1="6" x2="6" y2="18"></line><line x1="6" y1="6" x2="18" y2="18"></line></svg>

  <!-- Background, click to close -->
  <a href="#" data-modal-overlay></a>

Unique ID

Each modal should have a unique id as follows:

<div id="modal-one" data-modal>

Focus Trap

As you can see, once the modal is opened, when we keep pressing tab, each element of the modal is focused but as you keep pressing tab, the focus goes out of the modal and other website elements in the header are focused.

This is the default behaviour for every modal.

If you need to fix this, you need to add some javascript code so the focus will remain in the modal

Try focus-trap-js. Vanilla JS with size < 0.5kb. No dependencies.

Page Scroll

As far CSSUI is a Pure CSS library, the modal component doesn’t provide any page scroll lock feature. You need a dedicate Javascript script for it.

Try body-scroll-lock to enable it.


This is the list of variables related to this component. You can customize the design by changing or overriding these values:

  --modal-background: rgb(255, 255, 255);
  --modal-level: 9999;
  --modal-max-size: 500px;
  --modal-overlay-background: rgba(0, 0, 0, .2);
  --modal-radius: 8px;
  --modal-size: 80%;
  --modal-spacing: 1rem;