tailwind-grid-inner

This Tailwind plugin is for creating CSS grids with "inner" borders only, meaning that each item in the grid gets a border on every side that doesn't touch one of the four sides of the grid-container. If that's confusing, think of a tic-tac-toe board. The plugin results in grid-items of equal width (border-exclusive), and it supports "unbalanced" grids (where there aren't enough items to fill the last row).

• tailwind-grid-inner
  • Requirements
  • Installation
  • Usage
    • Important Notes (Read This!)
    • The none value

Requirements

• Tailwind 2.2.0 or higher (but only with JIT-mode enabled if using Tailwind 2)

Installation

First install the plugin from npm:

npm install @michaelallenwarner/tailwind-grid-inner

Then add it to your tailwind.config.js file. By default, this plugin uses the :where() pseudo-class, which isn't supported in Safari 13 and some other older browsers. If that's fine for your use-case, then just do:

// tailwind.config.js
module.exports = {
  theme: {
    // ...
  },
  plugins: [
    require('@michaelallenwarner/tailwind-grid-inner'),
    // ...
  ],
}

But if you have to support browsers that don't support :where(), then you can pass the plugin a { target: 'legacy' } object like this:

// tailwind.config.js
module.exports = {
  theme: {
    // ...
  },
  plugins: [
    require('@michaelallenwarner/tailwind-grid-inner')({ target: 'legacy' }),
    // ...
  ],
}

(The target: 'legacy' option works just as well, but it generates more CSS and makes use of some selectors that have higher specificity.)

Usage

Use the `grid-inner-${n}` utilities to create inner-border-only grids with n equally sized columns. Supported values for n are the numbers 1–12, but you can also supply arbitrary values like grid-inner-[n] or grid-inner-[n,m], where n is still the number of columns and where m is the desired border-width in pixels. Finally, there's grid-inner-none, which is for "canceling" the inner-grid layout altogether and is meant to be used with responsive variants (more on this below).

<div class="overflow-hidden"><!-- (if overflow is a problem; see notes below) -->
  <!-- grid-wrapper --> 
  <div class="grid-inner-1 sm:grid-inner-[2,4] md:grid-inner-3 lg:grid-inner-none border-red-500 border-solid">
    <!-- grid-items -->
    <div></div>
    <div></div>
    <div></div>
    <!-- etc. -->
  </div>
</div>

Important Notes (Read This!)

• The grid-wrapper gets a bit of negative horizontal margin. This should never result in visible overflow, but in rare cases it may result in scrollbars. To guard against this (or to fix it when it happens), you can just put the grid-wrapper in a <div> that has overflow: hidden, as in the example above.
• To control space around the grid-wrapper, do so on a separate outer wrapping <div>.
• To space the grid-items, give them (or elements in them) padding.
• Don't:
  • set gap on the grid-wrapper;
  • set margin or border-width on either the grid-wrapper or the grid-items;
  • set grid-column on the grid-items (the Tailwind col-span- utilities);
  • set position on the grid-items;
  • create ::after pseudo-elements on the grid-items.
• To control the color and style of the borders, put your border-color and border-style utility classes on the grid-wrapper rather than on its grid-item children. (The plugin gives the grid-items border-color: inherit and border-style: inherit.)
• The border-width m you supply with grid-inner-[n,m] syntax should be an even integer. If it isn't then it will be rounded up to one before it's used. The reason for this has to do with how the borders are applied. Because there's no border-collapse mechanism for CSS Grid, each grid-item's border will actually be half the width of the configured value, so that when two borders meet the result will look like a border of the correct width. Since 1/2-pixel values don't render reliably across devices, the plugin enforces integer-pixel values for these "half"-borders. The default and minimum-allowed value of m is 2.
• Because each border is technically two separate "half"-borders that touch, some border-styles might not look how you'd expect them to, and this will be more noticeable with thicker borders. For this reason, I recommend sticking with solid borders, but feel free to experiment!

The none value

Since this plugin relies on some gnarly CSS under the hood (including some negative margins, pseudo-elements, and lots of :nth-child()/:nth-last-child() pseudo-classes), it comes with a grid-inner-none utility that "cancels" some of that CSS, in case you have to switch to another kind of layout at some breakpoint. Here is what it does:

• On the grid-container, it sets marginLeft: 0px and marginRight: 0px. If you have need to override these margins, you'll find that a simple Tailwind class won't suffice, and you may need to bump the specificity (e.g., lg:grid-inner-none lg:mx-4 won't work, but lg:grid-inner-none lg:!mx-4 will).
• On the grid-items, it sets margin: 0px, border-width: 0px, border-color: currentcolor, border-style: solid, grid-column: auto, and position: static. Here too you'll find that simple Tailwind classes on the grid-items will lack the specificity to override these properties, and you may need to bump the specificity (like lg:!m-4).
• It sets the ::after pseudo-element on the grid-items to display: none, and the same specificity-bump caveat applies here. What's more: if you try to use the ::after pseudo-element on a grid-item (at a breakpoint where grid-inner-none is in effect), you'll sometimes find that some CSS properties are already set on it, and that overriding them requires more specificity-bumps. So if the need arises, reach for ::before instead.

Note that the grid-container will still have display: grid, gap: 0px, and whatever grid-template-columns value is currently active. But these properties can be overridden with simple Tailwind classes (like lg:grid-inner-none lg:block or lg:grid-inner-none lg:grid-cols-4 lg:gap-4).

Finally, note that the specificity required to override the grid-inner-none styles on the grid-items will depend on whether you've configured the plugin with the target: 'legacy' option.