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.
Culture
Pack your bags, we will do the rest
From city breaks to safaris, we plan trips around how you like to travel.
<div class="bg-body border rounded-3 p-3 shadow-sm" style="max-width:22rem">
<p class="small text-body-secondary text-uppercase fw-semibold mb-1">Culture</p>
<h3 class="h5 mb-2">Pack your bags, we will do the rest</h3>
<p class="mb-0 text-body-secondary">From city breaks to safaris, we plan trips around how you like to travel.</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-3 p-3 bg-body-tertiary">
<div class="d-none d-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="d-flex d-md-none">
<button type="button" class="btn btn-sm btn-primary w-100"><i class="bi bi-three-dots" aria-hidden="true"></i> Actions</button>
</div>
<p class="small text-body-secondary 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 (the labels sit under it, so they stay readable on every step).
<div class="d-flex flex-wrap gap-3 small text-center">
<div>
<div class="bg-primary rounded-2 mb-1" style="width:3.5rem;height:2.5rem;--ui-bg-opacity:1">
</div>
1
</div>
<div>
<div class="bg-primary rounded-2 mb-1" style="width:3.5rem;height:2.5rem;--ui-bg-opacity:.6">
</div>
.6
</div>
<div>
<div class="bg-primary rounded-2 mb-1" style="width:3.5rem;height:2.5rem;--ui-bg-opacity:.35">
</div>
.35
</div>
<div>
<div class="bg-primary rounded-2 mb-1" style="width:3.5rem;height:2.5rem;--ui-bg-opacity:.15">
</div>
.15
</div>
<div>
<div class="bg-primary rounded-2 mb-1 border" style="width:3.5rem;height:2.5rem;--ui-bg-opacity:.05">
</div>
.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-3 p-3 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-3 p-3 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-3 p-3 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-3 p-3 text-center small" style="--ui-border-opacity:.1">
.1
</div>
</div>
</div>5State via --ui-link-opacity
Coloured links read --ui-link-opacity: fade a link that is not available yet, or fade on hover - a link people must read stays at full strength.
- Guided tours --ui-link-opacity:.5, not available
- Best price guarantee 100, 75 on hover
- The world is waiting for you link-danger, faint underline
<ul class="list-unstyled mb-0 d-grid gap-2">
<li><a href="#" class="link-primary pe-none" style="--ui-link-opacity:.5" aria-disabled="true" tabindex="-1">Guided tours</a> <span class="small text-body-secondary">--ui-link-opacity:.5, not available</span></li>
<li><a href="#" class="link-primary link-opacity-100 link-opacity-75-hover">Best price guarantee</a> <span class="small text-body-secondary">100, 75 on hover</span></li>
<li><a href="#" class="link-danger link-underline-opacity-25">The world is waiting for you</a> <span class="small text-body-secondary">link-danger, faint underline</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.
Clear prices, honest advice and no surprises along the way.
<div class="d-flex gap-3 align-items-start border rounded-3 p-3">
<img src="../assets/img/avatar-6.svg" alt="Jonah Brennan" width="48" height="48" class="rounded-circle flex-shrink-0">
<div class="flex-grow-1">
<div class="d-flex justify-content-between">
<strong>Jonah Brennan</strong><small class="text-body-secondary">just now</small>
</div>
<p class="mb-0 small">Clear prices, honest advice and no surprises along the way.</p>
</div>
</div>7Status badges without the badge component
Subtle backgrounds, emphasis text, small padding and rounded-pill compose a soft status label.
<div class="d-flex flex-wrap gap-2">
<span class="d-inline-flex align-items-center gap-1 px-2 py-1 rounded-pill small fw-medium bg-success-subtle text-success-emphasis border border-success-subtle"><i class="bi bi-check-circle-fill" aria-hidden="true"></i> Active</span> <span class="d-inline-flex align-items-center gap-1 px-2 py-1 rounded-pill small fw-medium bg-warning-subtle text-warning-emphasis border border-warning-subtle"><i class="bi bi-clock" aria-hidden="true"></i> Pending</span> <span class="d-inline-flex align-items-center gap-1 px-2 py-1 rounded-pill small fw-medium bg-danger-subtle text-danger-emphasis border border-danger-subtle"><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.
<div class="row g-3">
<div class="col-sm-6 col-lg-4">
<div class="p-3 rounded-4 bg-body-tertiary border">
<div class="d-flex justify-content-between align-items-center mb-2">
<span class="small text-body-secondary fw-medium">Revenue</span><span class="text-primary fs-5"><i class="bi bi-graph-up-arrow" aria-hidden="true"></i></span>
</div>
<div class="fs-3 fw-bold lh-1">
$29,458.30
</div>
<div class="small text-success mt-1">
<i class="bi bi-arrow-up" aria-hidden="true"></i> +94% this month
</div>
</div>
</div>
<div class="col-sm-6 col-lg-4">
<div class="p-3 rounded-4 bg-body-tertiary border">
<div class="d-flex justify-content-between align-items-center mb-2">
<span class="small text-body-secondary fw-medium">Customers</span><span class="text-info fs-5"><i class="bi bi-people" aria-hidden="true"></i></span>
</div>
<div class="fs-3 fw-bold lh-1">
5.8k
</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.
Online
Away
<div class="d-flex gap-4 align-items-center">
<div class="position-relative d-inline-block">
<img src="../assets/img/avatar-10.svg" alt="Noah Lindqvist" width="56" height="56" class="rounded-circle"> <span class="position-absolute bottom-0 end-0 p-2 bg-success border border-2 border-white rounded-circle"><span class="visually-hidden">Online</span></span>
</div>
<div class="position-relative d-inline-block">
<img src="../assets/img/avatar-7.svg" alt="Lea Kim" width="56" height="56" class="rounded-circle"> <span class="position-absolute bottom-0 end-0 p-2 bg-secondary border border-2 border-white rounded-circle"><span class="visually-hidden">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.
Your perfect holiday, planned for you
Thousands of travellers already trust us, and we work hard to keep it that way.
Get started<div class="p-4 rounded-4 bg-primary-subtle text-center text-md-start">
<h3 class="h4 fw-bold text-primary-emphasis">Your perfect holiday, planned for you</h3>
<p class="mb-3 text-primary-emphasis">Thousands of travellers already trust us, and we work hard to keep it that way.</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.
<div class="d-flex flex-column flex-md-row gap-3">
<div class="flex-fill p-3 rounded-3 border bg-body-tertiary">
<i class="bi bi-lightning-charge-fill" aria-hidden="true"></i> <strong>Best price guarantee</strong>
</div>
<div class="flex-fill p-3 rounded-3 border bg-body-tertiary">
<i class="bi bi-shield-check" aria-hidden="true"></i> <strong>Free cancellation</strong>
</div>
<div class="flex-fill p-3 rounded-3 border bg-body-tertiary">
<i class="bi bi-cloud-arrow-up" aria-hidden="true"></i> <strong>Flexible dates</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.
Local guides show you the places that never make it into guidebooks.
<div class="border-start border-4 border-warning bg-warning-subtle rounded-end-3 p-3">
<div class="fw-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">Local guides show you the places that never make it into guidebooks.</p>
</div>13Settings row
justify-content-between and align-items-center place a label on the left and a control on the right.
<div class="border rounded-3">
<div class="d-flex justify-content-between align-items-center p-3 border-bottom">
<div>
<div class="fw-medium">
Email alerts
</div>
<div class="small text-body-secondary">
Daily summary at 12:45
</div>
</div>
<span class="px-2 py-1 rounded-pill small bg-success text-white">On</span>
</div>
<div class="d-flex justify-content-between align-items-center p-3">
<div>
<div class="fw-medium">
Push notifications
</div>
<div class="small text-body-secondary">
Only mentions
</div>
</div>
<span class="px-2 py-1 rounded-pill small bg-body-secondary text-body-secondary">Off</span>
</div>
</div>14Announcement bar
text-bg-dark sets a contrasting text colour with the background; small and gap utilities do the rest.
<div class="text-bg-dark rounded-3 px-3 py-2 d-flex flex-wrap align-items-center justify-content-center gap-2 small">
<span class="badge text-bg-warning">New</span> <span>Small hotels with big character</span> <a href="#" class="link-light link-offset-2 fw-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.
<div class="d-flex flex-wrap gap-2">
<span class="px-3 py-1 rounded-pill text-bg-primary small">All</span> <span class="px-3 py-1 rounded-pill border small">case study</span> <span class="px-3 py-1 rounded-pill border small">Adventure</span> <span class="px-3 py-1 rounded-pill border small">clear</span> <span class="px-3 py-1 rounded-pill border small">dashboard</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.
<div class="d-flex align-items-center gap-3 border rounded-3 p-2" style="max-width:28rem">
<img src="../assets/img/product-12.svg" alt="Surf camp" width="56" height="56" class="rounded-2 object-fit-cover flex-shrink-0">
<div class="flex-grow-1 overflow-hidden">
<div class="fw-medium text-truncate">
Surf camp - modern edition
</div>
<div class="small text-body-secondary">
Beach
</div>
</div>
<div class="fw-bold text-nowrap">
$518.00
</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.
A beginner's guide to getting started
Start in minutes and get help from a real person whenever you need it. We measure success by how many travellers come back and tell their friends.
<div class="border rounded-4 p-2 p-md-4 bg-body-tertiary">
<h3 class="h6 mb-2 mb-md-3">A beginner's guide to getting started</h3>
<p class="mb-0 small">Start in minutes and get help from a real person whenever you need it. We measure success by how many travellers come back and tell their friends.</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="d-flex flex-wrap gap-3" 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.
<div class="position-relative rounded-4 overflow-hidden" style="max-width:26rem">
<img src="https://images.unsplash.com/photo-1529260830199-42c24126f198?auto=format&fit=crop&w=1200&h=800&q=70" alt="Find your next escape" class="w-100 d-block">
<div class="position-absolute bottom-0 start-0 end-0 bg-dark text-white p-3" style="--ui-bg-opacity:.6">
<div class="small text-white-50">
Toronto
</div>
<div class="fw-semibold">
Weekends you will talk about for years
</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 team has done this many times, so you never have to guess.
<div class="d-flex flex-column align-items-center text-center py-5 px-3 border rounded-4 bg-body-tertiary">
<div class="fs-1 text-body-tertiary mb-2">
<i class="bi bi-folder2-open" aria-hidden="true"></i>
</div>
<h3 class="h6 fw-semibold mb-1">No files yet</h3>
<p class="small text-body-secondary mb-3">Our team has done this many times, so you never have to guess.</p>
<button type="button" class="btn btn-sm btn-primary"><i class="bi bi-cloud-arrow-up" aria-hidden="true"></i> Upload</button>
</div>