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.
Keynote
Where great ideas meet
The networking app helps you meet the right people before you arrive.
<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">Keynote</p>
<h3 class="h5 mb-2">Where great ideas meet</h3>
<p class="mb-0 text-body-secondary">The networking app helps you meet the right people before you arrive.</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-fill" aria-hidden="true"></i> Share</button>
<button type="button" class="btn btn-sm btn-outline-danger"><i class="bi bi-trash3-fill" 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.
- Venue booking --ui-link-opacity:.5, not available
- Certificates 100, 75 on hover
- Ideas on stage, connections everywhere 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">Venue booking</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">Certificates</a> <span class="small text-body-secondary">100, 75 on hover</span></li>
<li><a href="#" class="link-danger link-underline-opacity-25">Ideas on stage, connections everywhere</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.
More than eighty speakers share what they have learned the hard way.
<div class="d-flex gap-3 align-items-start border rounded-3 p-3">
<img src="../assets/img/avatar-11.svg" alt="Kenji Quinn" width="48" height="48" class="rounded-circle flex-shrink-0">
<div class="flex-grow-1">
<div class="d-flex justify-content-between">
<strong>Kenji Quinn</strong><small class="text-body-secondary">yesterday</small>
</div>
<p class="mb-0 small">More than eighty speakers share what they have learned the hard 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-fill" 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">
$13,661.34
</div>
<div class="small text-success mt-1">
<i class="bi bi-arrow-up" aria-hidden="true"></i> +39% 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-fill" aria-hidden="true"></i></span>
</div>
<div class="fs-3 fw-bold lh-1">
5.3k
</div>
<div class="small text-danger mt-1">
<i class="bi bi-arrow-down" aria-hidden="true"></i> -7% 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-4.svg" alt="Diego Haddad" 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-8.svg" alt="Noah Rossi" 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.
Learn, connect and get inspired
We measure success by how many attendees come back and tell their friends.
Get started<div class="p-4 rounded-4 bg-primary-subtle text-center text-md-start">
<h3 class="h4 fw-bold text-primary-emphasis">Learn, connect and get inspired</h3>
<p class="mb-3 text-primary-emphasis">We measure success by how many attendees come back and tell their friends.</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>Hands-on workshops</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>Mobile agenda</strong>
</div>
<div class="flex-fill p-3 rounded-3 border bg-body-tertiary">
<i class="bi bi-cloud-arrow-up-fill" aria-hidden="true"></i> <strong>Hands-on workshops</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.
Every attendee receives a certificate of participation.
<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">Every attendee receives a certificate of participation.</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 18:00
</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>Be in the room where it happens</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">tips</span> <span class="px-3 py-1 rounded-pill border small">Panel</span> <span class="px-3 py-1 rounded-pill border small">bright</span> <span class="px-3 py-1 rounded-pill border small">routine</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-9.svg" alt="Masterclass" 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">
Masterclass - fast edition
</div>
<div class="small text-body-secondary">
Workshop
</div>
</div>
<div class="fw-bold text-nowrap">
$228.99
</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.
Highlights from last year's workshops
Thousands of attendees already trust us, and we work hard to keep it that way. Our team has done this many times, so you never have to guess.
<div class="border rounded-4 p-2 p-md-4 bg-body-tertiary">
<h3 class="h6 mb-2 mb-md-3">Highlights from last year's workshops</h3>
<p class="mb-0 small">Thousands of attendees already trust us, and we work hard to keep it that way. Our team has done this many times, so you never have to guess.</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-1769798643655-e0f10f62c3fd?auto=format&fit=crop&w=1200&h=800&q=70" alt="Learn from the best, meet the rest" 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">
Lisbon
</div>
<div class="fw-semibold">
Join the conference of the year
</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
Sponsors meet decision-makers in a relaxed, friendly setting.
<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">Sponsors meet decision-makers in a relaxed, friendly setting.</p>
<button type="button" class="btn btn-sm btn-primary"><i class="bi bi-cloud-arrow-up-fill" aria-hidden="true"></i> Upload</button>
</div>