How to Customize Text Decoration Thickness in Tailwind CSS

Tailwind CSS is a utility-first CSS framework that provides a wide range of classes to help you style your HTML elements quickly and efficiently. One of the many aspects of styling that Tailwind covers is text decoration, which includes properties like underline, line-through, and overline. In this article, we’ll focus on how to control the thickness of text decorations using Tailwind CSS.

Understanding Text Decoration in CSS

Before diving into Tailwind specifics, it’s important to understand the CSS property that controls text decoration thickness. The text-decoration-thickness property in CSS allows you to specify the thickness of the lines used for text decoration. It can take values like auto, from-font, lengths (e.g., 2px), or percentages.

Tailwind CSS and Text Decoration Thickness

Tailwind CSS, as of version 2.0, doesn’t include utility classes for text-decoration-thickness out of the box. However, Tailwind is highly customizable, and you can extend it to include these utilities.

Step 1: Extending Tailwind CSS

To add text decoration thickness utilities, you need to extend Tailwind’s default theme in your tailwind.config.js file. Here’s how you can do it:

// tailwind.config.js
module.exports = {
  theme: {
    extend: {
      textDecorationThickness: {
        '1': '1px',
        '2': '2px',
        '4': '4px',
        // Add as many custom values as you need
  variants: {
    // Enable variants for textDecorationThickness if needed
    textDecorationThickness: ['responsive', 'hover', 'focus'],
  plugins: [],

Step 2: Using the Custom Utilities in Your HTML

Once you’ve extended your Tailwind configuration, you can use the new utilities in your HTML just like any other Tailwind class:

<p class="underline text-decoration-thickness-2">
  This text will have a 2px thick underline.

Step 3: Considering Browser Support

Keep in mind that the text-decoration-thickness property is relatively new and may not be supported in all browsers. Check the MDN Web Docs for up-to-date browser compatibility information.

Handling Fallbacks

For browsers that do not support text-decoration-thickness, you may want to provide a fallback. You can do this by using custom CSS alongside your Tailwind classes:

/* styles.css */
.fallback-decoration-thickness {
  text-decoration: underline;
  text-decoration-thickness: 2px;

/* For browsers that don't support text-decoration-thickness */
@supports not (text-decoration-thickness: 2px) {
  .fallback-decoration-thickness {
    text-decoration-style: double; /* or some other fallback */

Then, use the custom class in your HTML:

<p class="fallback-decoration-thickness">
  This text will have a fallback if text-decoration-thickness is not supported.

Responsive and State Variants

Tailwind allows you to apply styles based on different states or screen sizes. If you’ve enabled variants for textDecorationThickness in your Tailwind config, you can use them like this:

<p class="underline text-decoration-thickness-2 hover:text-decoration-thickness-4">
  This text will have a thicker underline on hover.


Customizing text decoration thickness with Tailwind CSS requires extending the framework’s default theme. By adding your own utilities to the tailwind.config.js file, you can easily apply different text decoration thicknesses to your elements. Remember to consider browser support and provide fallbacks when necessary.

For more advanced customization and examples, check out the Tailwind CSS documentation on extending the theme. With Tailwind’s flexibility and your creativity, you can design text decorations that perfectly match your project’s aesthetic.


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