Converting existing CSS into Tailwind classes

Converting existing CSS into Tailwind classes

Chris Bongers
·Jan 22, 2021·

9 min read

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In part one, we started by styling the sidebar and menu for the lifestyle blog.

I started with custom SCSS classes, which resulted in the following result:

CSS Styled expanding menu

Yesterday we added Tailwind to our Eleventy project, so let's see how we can now change the frontend, so it styled once again.

Our initial project looks like this at the moment:

Unstyled tailwind markup

Ohno! This looks horrible, all our hard work is gone, but no worries, we will solve this!

Changing our SCSS to Tailwind

As you might know, Tailwind CSS is a utility-first CSS framework. It uses utility classes to achieve styling.

Luckily for us, we know exactly what we are looking for, we can then use the Tailwind Docs to search what the corresponding class is.

Let me document how I go about changing these.

Let's take the <main> element, for instance. This had the following CSS.

main {
  position: relative;
  min-height: 100vh;
  padding-left: (calc(2 * var(--side-width)));

Let's first find the position: relative type that into the tailwind search bar.

Tailwind search bar

We can then click on the first result and see that we need to use the relative class.

Tailwind Relative class

Let's add that to the markup:

<main class="relative"></main>

One down, two to go.

The second one is the min-height. We can use the same process and will find we need the min-h-screen class.

Min-height tailwind classes

Nice, we are getting somewhere. The last one is a bit of a difficult one since we used a fixed position of 58px for each element. Tailwind doesn't really work with fixed positions, although we could add them to our tailwind config. However, we will take the closest tailwind size, which is 14 (3.5rem), which converts to: 56px.

Getting back to our padding-left, we saw that we needed double that, so we use pl-28, which converts to padding-left: 7rem.

Our <main> element ends up with these classes:

<main class="relative min-h-screen pl-28"></main>

Styling the aside element

Our <aside> element had the following CSS.

aside {
  width: var(--side-width);
  background: var(--purple);
  min-height: 100vh;
  position: fixed;
  left: 0;
  display: flex;
  justify-content: center;
  align-items: flex-end;
  z-index: 2;

We will get back to the color in a second, but we can all achieve the other classes with tailwind classes.

The result looks like this:

  class="fixed top-0 left-0 z-10 flex items-end justify-center min-h-screen w-14"

This will result in the following:

Tailwind styling

Still a bit of a mess, so let's first move on to styling those social icons before adding the colors.

For the <ul>, we don't need any classes.

The <li> items had the following CSS.

li {
  width: var(--side-width);
  height: var(--side-width);
  display: flex;
  justify-content: center;
  align-items: center;
  border-top: 1px solid var(--white);

That converts into the following classes:

<li class="flex items-center justify-center border-t border-white w-14 h-14"></li>

Then the <a> elements inside looked like this:

a {
  width: 1.75rem;
  height: 1.75rem;
  display: flex;
  justify-content: center;
  align-items: center;
  border: 1px solid var(--white);
  border-radius: 50%;
  color: var(--white);

We can turn that into the following Tailwind classes.

  class="flex items-center justify-center text-white border border-white w-7 h-7 rounded-full"

The last element we need is the SVG

svg {
  color: inherit;
  width: 0.625em;

For the SVG, we can use these Tailwind classes.

<svg class="w-2.5"></svg>

Now, we won't see much since we need our purple background-color.

Adding custom colors to Tailwind

Unfortionally Tailwind doesn't come with this exact color, but it does come with the option to add our own colors!

To do this, we have to add our custom color in the tailwind.config.js file.

We can extend our custom color in the theme section under colors like so:

module.exports = {
  purge: [],
  darkMode: false, // or 'media' or 'class'
  theme: {
    extend: {
      colors: {
        purple: '#2d334d'
  variants: {
    extend: {}
  plugins: []

In our case, the purple only has one option.

Then we can go back to our aside element and add the bg-purple class to it.

This will now result in the following:

Styled tailwind classes

Wow, that already is starting to look like what we had.

Adding the expanding menu with Tailwind

Now let's see how we can style the menu to expand.

I'm going to be quickly going over the basic classes and spend more time explaining the checked state.

<nav> element CSS styling:

nav {
  width: var(--side-width);
  background: var(--light-blue);
  min-height: 100vh;
  position: fixed;
  left: var(--side-width);

Converted to Tailwind classes:

<nav class="fixed top-0 min-h-screen left-14 bg-light-blue w-14"></nav>

Note: we also added our light-blue color which looks like this:

colors: {
    'purple': "#2d334d",
    'light-blue': "#d5d8e0"

The menu than holds the following styling:

.menu {
  width: 170px;
  height: 100vh;
  background: inherit;
  position: absolute;
  top: 0;
  left: -170px;
  z-index: 1;
  transition: all 0.5s ease;
  overflow: hidden;

Which can be turned into the following Tailwind:

  class="absolute top-0 z-0 min-h-screen overflow-hidden transition-all duration-500 ease-in-out menu w-44 -left-44 bg-light-blue"

The checkbox can just get the hidden class:

<input type="checkbox" id="toggle" class="hidden menu--checkbox" />

As for the label, it looked like this in CSS

label {
  width: var(--side-width);
  height: var(--side-width);
  display: flex;
  justify-content: center;
  align-items: center;
  position: absolute;
  z-index: 3;

Which we can convert to this Tailwind:

  class="absolute z-30 flex items-center justify-center w-14 h-14"

I don't think the ~ selector is available in Tailwind, so we would have to write a little bit of custom CSS just for this selector.

main nav .menu--checkbox:checked ~ .menu {
  @apply left-0;

This will apply the left-0 class to our menu once the checkbox is checked.

Let's see if it works:

Tailwind CSS Menu

Nice! All we have to do is the actual menu styling.

The CSS before for the logo

.menu {
  &--logo {
    margin-top: 6rem;
    display: flex;
    justify-content: center;
    img {
      width: 85px;

Which can be converted to:

<a href="/" class="flex justify-center mt-24">
  <img class="w-20" src="" />

Then the list had the following CSS:

ul {
  margin-top: 2.5rem;
  li {
    padding: 0 25px 25px;
    color: var(--purple);
    a {
      color: inherit;
      text-decoration: none;

That we can convert into Tailwind as such:

<ul class="mt-10">
  <li class="px-6 pb-6"><a class="no-underline text-purple" href="#">Home</a></li>

Now we should have the end result we had before, but all in Tailwind classes!

Complete menu in Tailwind classes

You can find these amended changed on GitHub.

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