Utilities for controlling the stack order of an element.
Control the stack order (or three-dimensional positioning) of an element in Tailwind, regardless of order it has been displayed, using the z-{index} utilities.
<div class="z-40 ...">5</div>
<div class="z-30 ...">4</div>
<div class="z-20 ...">3</div>
<div class="z-10 ...">2</div>
<div class="z-0 ...">1</div>To control the z-index of an element at a specific breakpoint, add a {screen}: prefix to any existing z-index utility. For example, use md:z-50 to apply the z-50 utility at only medium screen sizes and above.
<div class="z-0 md:z-50 ...">
  <!-- ... -->
</div>For more information about Tailwind's responsive design features, check out the Responsive Design documentation.
By default Tailwind provides six numeric z-index utilities and an auto utility. You change, add, or remove these by editing the theme.zIndex section of your Tailwind config.
  // tailwind.config.js
  module.exports = {
    theme: {
      zIndex: {
        '0': 0,
-       '10': 10,
-       '20': 20,
-       '30': 30,
-       '40': 40,
-       '50': 50,
+       '25': 25,
+       '50': 50,
+       '75': 75,
+       '100': 100,
        'auto': 'auto',
      }
    }
  }If you'd like to add any negative z-index classes that take the same form as Tailwind's negative margin classes, prefix the keys in your config file with a dash:
  // tailwind.config.js
  module.exports = {
    theme: {
      extend: {
        zIndex: {
+         '-10': '-10',
        }
      }
    }
  }Tailwind is smart enough to generate classes like -z-10 when it sees the leading dash, not z--10 like you might expect.
By default, only responsive, focus-within and focus variants are generated for z-index utilities.
You can control which variants are generated for the z-index utilities by modifying the zIndex property in the variants section of your tailwind.config.js file.
For example, this config will also generate hover and active variants:
  // tailwind.config.js
  module.exports = {
    variants: {
      extend: {
        // ...
+       zIndex: ['hover', 'active'],
      }
    }
  }If you don't plan to use the z-index utilities in your project, you can disable them entirely by setting the zIndex property to false in the corePlugins section of your config file:
  // tailwind.config.js
  module.exports = {
    corePlugins: {
      // ...
+     zIndex: false,
    }
  }