Utility API

Utilities are single-purpose classes that you combine directly in markup. Stack several on one element, add a breakpoint infix such as d-md-flex to change behaviour from a screen size up, and tune colour states through CSS variables like --ui-bg-opacity, --ui-border-opacity and --ui-link-opacity. The recipes below build complete interface pieces without writing any custom CSS.

1A card made only of utilities

Background, border, radius, padding and shadow utilities stacked on a plain div give you a card without the card component.

Environment

Join a community that cares

A friendly update guides results you can measure without the usual hassle.

<div class="bg-page border rounded-lg p-4 shadow-sm" style="max-width:22rem">
  <p class="small text-muted uppercase font-semibold mb-1">Environment</p>
  <h3 class="h5 mb-2">Join a community that cares</h3>
  <p class="mb-0 text-muted">A friendly update guides results you can measure without the usual hassle.</p>
</div>

2Responsive display: d-none d-md-flex

Breakpoint infixes switch a utility on from a screen size up. Resize the window: the toolbar row appears from md, the compact button below it.

d-none d-md-flex and d-flex d-md-none

<div class="border rounded-lg p-4 bg-surface-3">
  <div class="hidden md:flex gap-2">
    <button type="button" class="btn btn-sm btn-primary"><i class="bi bi-pencil-square" aria-hidden="true"></i> Edit</button>
    <button type="button" class="btn btn-sm btn-outline-secondary"><i class="bi bi-share" aria-hidden="true"></i> Share</button>
    <button type="button" class="btn btn-sm btn-outline-danger"><i class="bi bi-trash3" aria-hidden="true"></i> Delete</button>
  </div>
  <div class="flex md:hidden">
    <button type="button" class="btn btn-sm btn-primary w-full"><i class="bi bi-three-dots" aria-hidden="true"></i> Actions</button>
  </div>
  <p class="small text-muted mt-2 mb-0"><code>d-none d-md-flex</code> and <code>d-flex d-md-none</code></p>
</div>

3State via --ui-bg-opacity

Every bg-{colour} reads the --ui-bg-opacity variable, so one inline variable fades the fill while the text stays fully opaque.

.35

.15

.05

<div class="flex flex-wrap gap-2">
  <div class="bg-primary text-white rounded-md px-4 py-2" style="--ui-bg-opacity:1">
    1
  </div>
  <div class="bg-primary rounded-md px-4 py-2" style="--ui-bg-opacity:.6">
    .6
  </div>
  <div class="bg-primary rounded-md px-4 py-2" style="--ui-bg-opacity:.35">
    .35
  </div>
  <div class="bg-primary rounded-md px-4 py-2" style="--ui-bg-opacity:.15">
    .15
  </div>
  <div class="bg-primary rounded-md px-4 py-2" style="--ui-bg-opacity:.05">
    .05
  </div>
</div>

4State via --ui-border-opacity

Border colour utilities read --ui-border-opacity; set it inline for values between the border-opacity-* steps.

<div class="row g-2">
  <div class="col-6 col-md-3">
    <div class="border border-2 border-success rounded-lg p-4 text-center small" style="--ui-border-opacity:1">
      1
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="border border-2 border-success rounded-lg p-4 text-center small" style="--ui-border-opacity:.6">
      .6
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="border border-2 border-success rounded-lg p-4 text-center small" style="--ui-border-opacity:.3">
      .3
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="border border-2 border-success rounded-lg p-4 text-center small" style="--ui-border-opacity:.1">
      .1
    </div>
  </div>
</div>

5State via --ui-link-opacity

Coloured links read --ui-link-opacity. Combine it with the -hover utilities for a link that brightens on hover.

Disaster response --ui-link-opacity:.5
Tax receipts 50, 100 on hover
Small acts, big impact link-opacity-75

<ul class="list-unstyled mb-0 grid gap-2">
  <li><a href="#" class="link-primary" style="--ui-link-opacity:.5">Disaster response</a> <span class="small text-muted">--ui-link-opacity:.5</span></li>
  <li><a href="#" class="link-primary link-opacity-50 link-opacity-100-hover">Tax receipts</a> <span class="small text-muted">50, 100 on hover</span></li>
  <li><a href="#" class="link-danger link-opacity-75">Small acts, big impact</a> <span class="small text-muted">link-opacity-75</span></li>
</ul>

6Media object

d-flex with gap, flex-shrink-0 on the image and flex-grow-1 on the text is the classic comment or list row.

Aria Duarteyesterday

Our disaster response helps your work organised wherever you are.

<div class="flex gap-4 items-start border rounded-lg p-4">
  <img src="../assets/img/avatar-5.svg" alt="Aria Duarte" width="48" height="48" class="rounded-full shrink-0"> 
  <div class="grow">
    <div class="flex justify-between">
      <strong>Aria Duarte</strong><small class="text-muted">yesterday</small>
    </div>
    <p class="mb-0 small">Our disaster response helps your work organised wherever you are.</p>
  </div>
</div>

7Status badges without the badge component

Subtle backgrounds, emphasis text, small padding and rounded-pill compose a soft status label.

Active Pending Blocked

<div class="flex flex-wrap gap-2">
  <span class="inline-flex items-center gap-1 px-2 py-1 rounded-full small font-medium bg-success-subtle text-success-emphasis border border-success/30"><i class="bi bi-check-circle-fill" aria-hidden="true"></i> Active</span> <span class="inline-flex items-center gap-1 px-2 py-1 rounded-full small font-medium bg-warning-subtle text-warning-emphasis border border-warning/30"><i class="bi bi-clock" aria-hidden="true"></i> Pending</span> <span class="inline-flex items-center gap-1 px-2 py-1 rounded-full small font-medium bg-danger-subtle text-danger-emphasis border border-danger/30"><i class="bi bi-x-circle-fill" aria-hidden="true"></i> Blocked</span> 
</div>

8Stat tile

Font size, weight, line height and colour utilities turn three lines of text into a dashboard metric.

Revenue

$39,715.51

+15% this month

Customers

2.0k

-5% this month

<div class="row g-3">
  <div class="col-sm-6 col-lg-4">
    <div class="p-4 rounded-xl bg-surface-3 border">
      <div class="flex justify-between items-center mb-2">
        <span class="small text-muted font-medium">Revenue</span><span class="text-primary text-lg"><i class="bi bi-graph-up-arrow" aria-hidden="true"></i></span>
      </div>
      <div class="text-2xl font-bold leading-none">
        $39,715.51
      </div>
      <div class="small text-success mt-1">
        <i class="bi bi-arrow-up" aria-hidden="true"></i> +15% this month
      </div>
    </div>
  </div>
  <div class="col-sm-6 col-lg-4">
    <div class="p-4 rounded-xl bg-surface-3 border">
      <div class="flex justify-between items-center mb-2">
        <span class="small text-muted font-medium">Customers</span><span class="text-info text-lg"><i class="bi bi-people" aria-hidden="true"></i></span>
      </div>
      <div class="text-2xl font-bold leading-none">
        2.0k
      </div>
      <div class="small text-danger mt-1">
        <i class="bi bi-arrow-down" aria-hidden="true"></i> -5% this month
      </div>
    </div>
  </div>
</div>

9Avatar with a status dot

position-relative on the wrapper, then position-absolute, bottom-0 / end-0 and a white border for the online dot.

<div class="flex gap-6 items-center">
  <div class="relative inline-block">
    <img src="../assets/img/avatar-7.svg" alt="Mateo Hughes" width="56" height="56" class="rounded-full"> <span class="absolute bottom-0 end-0 p-2 bg-success border border-2 border-white rounded-full"><span class="sr-only">Online</span></span> 
  </div>
  <div class="relative inline-block">
    <img src="../assets/img/avatar-2.svg" alt="Ivy Ortega" width="56" height="56" class="rounded-full"> <span class="absolute bottom-0 end-0 p-2 bg-secondary border border-2 border-white rounded-full"><span class="sr-only">Away</span></span> 
  </div>
</div>

10Responsive alignment

text-center on phones and text-md-start from md: a hero block that centres only where it should.

Help us build a kinder world

The new volunteer network lets you focused on what matters on any device.

Get started

<div class="p-6 rounded-xl bg-primary-subtle text-center md:text-start">
  <h3 class="h4 font-bold text-primary-emphasis">Help us build a kinder world</h3>
  <p class="mb-4 text-primary-emphasis">The new volunteer network lets you focused on what matters on any device.</p>
  <a href="#" class="btn btn-primary">Get started</a> 
</div>

11Stack on phones, row on tablets

flex-column flex-md-row with gap-3: three blocks stack on small screens and line up from md.

Secure giving

Impact tracking

<div class="flex flex-col md:flex-row gap-4">
  <div class="flex-auto p-4 rounded-lg border bg-surface-3">
    <i class="bi bi-lightning-charge-fill" aria-hidden="true"></i> <strong>Secure giving</strong>
  </div>
  <div class="flex-auto p-4 rounded-lg border bg-surface-3">
    <i class="bi bi-shield-check" aria-hidden="true"></i> <strong>Secure giving</strong>
  </div>
  <div class="flex-auto p-4 rounded-lg border bg-surface-3">
    <i class="bi bi-cloud-arrow-up" aria-hidden="true"></i> <strong>Impact tracking</strong>
  </div>
</div>

12Callout from border-start

A single side border with a thick width and a theme colour makes a note or warning callout.

Heads up

The new secure giving makes results you can measure on any device.

<div class="border-s border-4 border-warning bg-warning-subtle rounded-end-3 p-4">
  <div class="font-semibold text-warning-emphasis mb-1">
    <i class="bi bi-exclamation-triangle-fill" aria-hidden="true"></i> Heads up
  </div>
  <p class="mb-0 small text-warning-emphasis">The new secure giving makes results you can measure on any device.</p>
</div>

13Settings row

justify-content-between and align-items-center place a label on the left and a control on the right.

Email alerts

Daily summary at 17:15

Push notifications

Only mentions

Off

<div class="border rounded-lg">
  <div class="flex justify-between items-center p-4 border-b">
    <div>
      <div class="font-medium">
        Email alerts
      </div>
      <div class="small text-muted">
        Daily summary at 17:15
      </div>
    </div>
    <span class="px-2 py-1 rounded-full small bg-success text-white">On</span> 
  </div>
  <div class="flex justify-between items-center p-4">
    <div>
      <div class="font-medium">
        Push notifications
      </div>
      <div class="small text-muted">
        Only mentions
      </div>
    </div>
    <span class="px-2 py-1 rounded-full small bg-surface-2 text-muted">Off</span> 
  </div>
</div>

14Announcement bar

text-bg-dark sets a contrasting text colour with the background; small and gap utilities do the rest.

New Join a community that cares Read more

<div class="text-bg-dark rounded-lg px-4 py-2 flex flex-wrap items-center justify-center gap-2 small">
  <span class="badge text-bg-warning">New</span> <span>Join a community that cares</span> <a href="#" class="link-light link-offset-2 font-semibold">Read more</a> 
</div>

15Filter chips that wrap

flex-wrap with gap-2 lets a row of chips flow onto new lines without margin hacks.

All guide Animals friendly process

<div class="flex flex-wrap gap-2">
  <span class="px-4 py-1 rounded-full bg-primary text-white small">All</span> <span class="px-4 py-1 rounded-full border small">guide</span> <span class="px-4 py-1 rounded-full border small">Animals</span> <span class="px-4 py-1 rounded-full border small">friendly</span> <span class="px-4 py-1 rounded-full border small">process</span> 
</div>

16Product line item

A thumbnail, a truncated title and a right-aligned price: overflow-hidden on the middle column lets text-truncate work in flex.

Shelter support - honest edition

Relief

$92.00

<div class="flex items-center gap-4 border rounded-lg p-2" style="max-width:28rem">
  <img src="../assets/img/product-4.svg" alt="Shelter support" width="56" height="56" class="rounded-md object-cover shrink-0"> 
  <div class="grow overflow-hidden">
    <div class="font-medium truncate">
      Shelter support - honest edition
    </div>
    <div class="small text-muted">
      Relief
    </div>
  </div>
  <div class="font-bold whitespace-nowrap">
    $92.00
  </div>
</div>

17Responsive spacing

p-2 p-md-4 and mb-2 mb-md-3: tighter padding on phones, roomier from md, no media query needed.

What's new in education

This clear experience lets your work organised without extra tools. The new volunteer network keeps the whole team on the same page all year round.

<div class="border rounded-xl p-2 md:p-6 bg-surface-3">
  <h3 class="h6 mb-2 md:mb-4">What&#39;s new in education</h3>
  <p class="mb-0 small">This clear experience lets your work organised without extra tools. The new volunteer network keeps the whole team on the same page all year round.</p>
</div>

18Underline that appears on hover

link-underline-opacity-0 hides the underline, the -hover variants bring it back with a little offset.

<nav class="flex flex-wrap gap-4" aria-label="Footer">
  <a href="#" class="link-body-emphasis link-offset-2 link-underline-opacity-0 link-underline-opacity-100-hover">About</a> <a href="#" class="link-body-emphasis link-offset-2 link-underline-opacity-0 link-underline-opacity-100-hover">Pricing</a> <a href="#" class="link-body-emphasis link-offset-2 link-underline-opacity-0 link-underline-opacity-100-hover">Support</a> <a href="#" class="link-body-emphasis link-offset-2 link-underline-opacity-0 link-underline-opacity-100-hover">Careers</a> 
</nav>

19Image with a text overlay

position-relative wrapper, an absolutely placed caption at bottom-0 and bg-dark with --ui-bg-opacity for the scrim.

Oslo

Together we can change lives

<div class="relative rounded-xl overflow-hidden" style="max-width:26rem">
  <img src="../assets/img/photo-1.svg" alt="Small acts, big impact" class="w-full block"> 
  <div class="absolute bottom-0 start-0 end-0 bg-dark text-white p-4" style="--ui-bg-opacity:.6">
    <div class="small text-white/50">
      Oslo
    </div>
    <div class="font-semibold">
      Together we can change lives
    </div>
  </div>
</div>

20Empty state panel

A centred flex column with a large icon, muted text and one action, built from spacing and text utilities.

No files yet

Our volunteer programs connects projects moving forward with friendly support.

<div class="flex flex-col items-center text-center py-12 px-4 border rounded-xl bg-surface-3">
  <div class="text-4xl text-muted/70 mb-2">
    <i class="bi bi-folder2-open" aria-hidden="true"></i>
  </div>
  <h3 class="h6 font-semibold mb-1">No files yet</h3>
  <p class="small text-muted mb-4">Our volunteer programs connects projects moving forward with friendly support.</p>
  <button type="button" class="btn btn-sm btn-primary"><i class="bi bi-cloud-arrow-up" aria-hidden="true"></i> Upload</button>
</div>