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.
Pediatrics
Care that puts you first
A secure workflow lets time back in your day all year round.
<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">Pediatrics</p>
<h3 class="h5 mb-2">Care that puts you first</h3>
<p class="mb-0 text-muted">A secure workflow lets time back in your day all year round.</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.
<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.
- Lab tests --ui-link-opacity:.5
- Certified specialists 50, 100 on hover
- Feel better with expert care link-opacity-75
<ul class="list-unstyled mb-0 grid gap-2">
<li><a href="#" class="link-primary" style="--ui-link-opacity:.5">Lab tests</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">Certified specialists</a> <span class="small text-muted">50, 100 on hover</span></li>
<li><a href="#" class="link-danger link-opacity-75">Feel better with expert care</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.
A elegant community connects results you can measure without the usual hassle.
<div class="flex gap-4 items-start border rounded-lg p-4">
<img src="../assets/img/avatar-2.svg" alt="Felix Duarte" width="48" height="48" class="rounded-full shrink-0">
<div class="grow">
<div class="flex justify-between">
<strong>Felix Duarte</strong><small class="text-muted">yesterday</small>
</div>
<p class="mb-0 small">A elegant community connects results you can measure without the usual hassle.</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="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.
<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">
$17,596.23
</div>
<div class="small text-success mt-1">
<i class="bi bi-arrow-up" aria-hidden="true"></i> +55% 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">
9.0k
</div>
<div class="small text-danger mt-1">
<i class="bi bi-arrow-down" aria-hidden="true"></i> -4% 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="flex gap-6 items-center">
<div class="relative inline-block">
<img src="../assets/img/avatar-3.svg" alt="Zoe Alvarez" 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-8.svg" alt="Ethan Okafor" 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.
Feel better with expert care
Our physiotherapy makes new ideas to life with friendly support.
Get started<div class="p-6 rounded-xl bg-primary-subtle text-center md:text-start">
<h3 class="h4 font-bold text-primary-emphasis">Feel better with expert care</h3>
<p class="mb-4 text-primary-emphasis">Our physiotherapy makes new ideas to life with friendly support.</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="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>Insurance friendly</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>Family plans</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>Family plans</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.
A flexible plan shows data easy to understand for teams of every size.
<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">A flexible plan shows data easy to understand for teams of every size.</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-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 07:30
</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.
<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>Book a doctor in minutes</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.
<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">tips</span> <span class="px-4 py-1 rounded-full border small">Dental</span> <span class="px-4 py-1 rounded-full border small">reliable</span> <span class="px-4 py-1 rounded-full border small">release</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="flex items-center gap-4 border rounded-lg p-2" style="max-width:28rem">
<img src="../assets/img/product-10.svg" alt="Annual check-up" width="56" height="56" class="rounded-md object-cover shrink-0">
<div class="grow overflow-hidden">
<div class="font-medium truncate">
Annual check-up - focused edition
</div>
<div class="small text-muted">
Dental
</div>
</div>
<div class="font-bold whitespace-nowrap">
$220.00
</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.
Project notes for patients
Our dental care gives data easy to understand from the very first day. Our physiotherapy connects complex tasks into simple steps for teams of every size.
<div class="border rounded-xl p-2 md:p-6 bg-surface-3">
<h3 class="h6 mb-2 md:mb-4">Project notes for patients</h3>
<p class="mb-0 small">Our dental care gives data easy to understand from the very first day. Our physiotherapy connects complex tasks into simple steps for teams of every size.</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.
<div class="relative rounded-xl overflow-hidden" style="max-width:26rem">
<img src="../assets/img/photo-12.svg" alt="Care that puts you first" 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">
Copenhagen
</div>
<div class="font-semibold">
Care that puts you first
</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
The new reminders gives customers coming back without the usual hassle.
<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">The new reminders gives customers coming back without the usual hassle.</p>
<button type="button" class="btn btn-sm btn-primary"><i class="bi bi-cloud-arrow-up" aria-hidden="true"></i> Upload</button>
</div>