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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.

Health

Join a community that cares

We have helped more than two hundred thousand people since we started.

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

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).

1
.6
.35
.15
.05

4State via --ui-border-opacity

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

1
.6
.3
.1

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.

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.

Diego Ashford
Diego Ashfordjust now

Volunteers give their time in schools, shelters and food banks every week.

7Status badges without the badge component

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

Active Pending Blocked

8Stat tile

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

Revenue
$28,183.47
+25% this month
Customers
3.4k
-8% this month

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.

Noah Ortega Online
Owen Duarte Away

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

A school kit costs less than a cinema ticket and lasts a whole year.

Get started

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.

Transparent reports
Transparent reports
Transparent reports

12Callout from border-start

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

Heads up

We measure success by how many donors come back and tell their friends.

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 07:15
On
Push notifications
Only mentions
Off

14Announcement bar

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

New Together we can change lives Read more

15Filter chips that wrap

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

All guide Relief flexible journey

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.

Tree planting
Tree planting - elegant edition
Environment
$10.00

17Responsive spacing

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

The small habits that make a big difference

Leave a gift in your will and help future generations. Thousands of donors already trust us, and we work hard to keep it that way.

18Underline that appears on hover

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

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.

Your kindness travels further than you think
Dublin
Change one life, change a community

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

Clear prices, honest advice and no surprises along the way.