Background

Background utilities paint an element with a theme colour, a subtle tint, the body surface or a gradient. Combine bg-{colour} with bg-opacity-* or the --ui-bg-opacity variable to fade it, and prefer the text-bg-* helpers or -emphasis text colours so contrast stays readable in light and dark mode.

1Theme colour backgrounds

bg-primary to bg-dark fill an element with a theme colour. Pair them with a readable text colour - text-bg-primary picks the one that reads on your brand colour.

bg-primary

bg-secondary

bg-success

bg-danger

bg-warning

bg-info

bg-light

bg-dark

<div class="row g-2 small">
  <div class="col-6 col-md-3">
    <div class="text-bg-primary rounded-md p-4">
      bg-primary
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="text-bg-secondary rounded-md p-4">
      bg-secondary
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="bg-success text-white rounded-md p-4">
      bg-success
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="bg-danger text-white rounded-md p-4">
      bg-danger
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="bg-warning text-dark rounded-md p-4">
      bg-warning
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="bg-info text-dark rounded-md p-4">
      bg-info
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="bg-light text-dark rounded-md p-4 border">
      bg-light
    </div>
  </div>
  <div class="col-6 col-md-3">
    <div class="text-bg-dark rounded-md p-4">
      bg-dark
    </div>
  </div>
</div>

2Subtle backgrounds

The -subtle variants are soft tints that work in light and dark mode; use the matching -emphasis text colour.

bg-primary-subtle

bg-success-subtle

bg-warning-subtle

bg-danger-subtle

bg-info-subtle

<div class="grid gap-2">
  <div class="bg-primary-subtle text-primary-emphasis rounded-lg px-4 py-2">
    bg-primary-subtle
  </div>
  <div class="bg-success-subtle text-success-emphasis rounded-lg px-4 py-2">
    bg-success-subtle
  </div>
  <div class="bg-warning-subtle text-warning-emphasis rounded-lg px-4 py-2">
    bg-warning-subtle
  </div>
  <div class="bg-danger-subtle text-danger-emphasis rounded-lg px-4 py-2">
    bg-danger-subtle
  </div>
  <div class="bg-info-subtle text-info-emphasis rounded-lg px-4 py-2">
    bg-info-subtle
  </div>
</div>

3Body backgrounds

bg-body, bg-body-secondary and bg-body-tertiary follow the page surface and adapt to colour mode.

bg-body - the page itself

bg-body-secondary - side panels

bg-body-tertiary - wells and inputs

<div class="border rounded-xl overflow-hidden">
  <div class="bg-page p-4 border-b">
    <code>bg-body</code> - the page itself
  </div>
  <div class="bg-surface-2 p-4 border-b">
    <code>bg-body-secondary</code> - side panels
  </div>
  <div class="bg-surface-3 p-4">
    <code>bg-body-tertiary</code> - wells and inputs
  </div>
</div>

4Text and background together

text-bg-{colour} sets the background and a contrasting text colour in one class.

text-bg-primary text-bg-warning text-bg-info text-bg-light text-bg-dark

<div class="flex flex-wrap gap-2">
  <span class="text-bg-primary rounded-full px-4 py-1">text-bg-primary</span> <span class="text-bg-warning rounded-full px-4 py-1">text-bg-warning</span> <span class="text-bg-info rounded-full px-4 py-1">text-bg-info</span> <span class="text-bg-light rounded-full px-4 py-1 border">text-bg-light</span> <span class="text-bg-dark rounded-full px-4 py-1">text-bg-dark</span> 
</div>

5Background opacity steps

bg-opacity-10, -25, -50, -75 and -100 fade a theme background in fixed steps. White text needs the full colour; the labels sit under the lighter steps.

100

<div class="flex flex-wrap gap-4 small text-center">
  <div>
    <div class="bg-success/100 rounded-lg mb-1" style="width:4rem;height:3rem">
    </div>
    100
  </div>
  <div>
    <div class="bg-success/75 rounded-lg mb-1" style="width:4rem;height:3rem">
    </div>
    75
  </div>
  <div>
    <div class="bg-success/50 rounded-lg mb-1" style="width:4rem;height:3rem">
    </div>
    50
  </div>
  <div>
    <div class="bg-success/25 rounded-lg mb-1" style="width:4rem;height:3rem">
    </div>
    25
  </div>
  <div>
    <div class="bg-success/10 rounded-lg mb-1" style="width:4rem;height:3rem">
    </div>
    10
  </div>
</div>

6Gradient overlay

bg-gradient adds a soft white-to-transparent gradient on top of any bg-{colour}.

bg-primary bg-gradient

Dark mode

bg-dark bg-gradient

Audit trail

<div class="row g-2">
  <div class="col-sm-6">
    <div class="bg-primary bg-gradient text-white rounded-xl p-6">
      <div class="font-semibold">
        bg-primary bg-gradient
      </div>
      <div class="small text-white/50">
        Dark mode
      </div>
    </div>
  </div>
  <div class="col-sm-6">
    <div class="bg-dark bg-gradient text-white rounded-xl p-6">
      <div class="font-semibold">
        bg-dark bg-gradient
      </div>
      <div class="small text-white/50">
        Audit trail
      </div>
    </div>
  </div>
</div>

7Transparent background

bg-transparent removes a fill, useful when a component's default background must disappear.

bg-white

bg-transparent

<div class="bg-surface-3 rounded-lg p-4 flex flex-wrap gap-2">
  <div class="bg-white text-dark border rounded-md px-4 py-2 small">
    bg-white
  </div>
  <div class="bg-transparent border rounded-md px-4 py-2 small">
    bg-transparent
  </div>
  <button type="button" class="btn btn-light bg-transparent border-0 text-body"><i class="bi bi-three-dots" aria-hidden="true"></i> Ghost button</button>
</div>

8Black and white

bg-black and bg-white are fixed colours that do not change with colour mode, unlike bg-body.

bg-black

bg-white

<div class="flex rounded-lg overflow-hidden border">
  <div class="bg-black text-white flex-auto p-4 text-center small">
    bg-black
  </div>
  <div class="bg-white text-black flex-auto p-4 text-center small">
    bg-white
  </div>
</div>

9Highlighted table row

Background utilities on a table cell or row mark a selection without extra CSS.

Order	Customer	Total
#TX-6155	Mia Sato	$180.36
#TX-1831	Ella Lindqvist	$112.80
#ORD-3942	Nadia Hughes	$246.81

<div class="table-responsive">
  <table class="table table-sm mb-0 align-middle">
    <thead>
      <tr>
        <th scope="col">Order</th>
        <th scope="col">Customer</th>
        <th scope="col" class="text-end">Total</th>
      </tr>
    </thead>
    <tbody>
      <tr>
        <td>#TX-6155</td>
        <td>Mia Sato</td>
        <td class="text-end">$180.36</td>
      </tr>
      <tr>
        <td class="bg-primary-subtle">#TX-1831</td>
        <td class="bg-primary-subtle">Ella Lindqvist</td>
        <td class="bg-primary-subtle text-end font-semibold">$112.80</td>
      </tr>
      <tr>
        <td>#ORD-3942</td>
        <td>Nadia Hughes</td>
        <td class="text-end">$246.81</td>
      </tr>
    </tbody>
  </table>
</div>

10Feature icons on tinted circles

A subtle background with rounded-circle and fixed size gives each icon a soft colour badge.

Open API

Audit trail

Open API

<div class="row g-3">
  <div class="col-sm-4 flex gap-2 items-center">
    <span class="bg-primary-subtle text-primary-ink rounded-full inline-flex items-center justify-center text-lg" style="width:44px;height:44px"><i class="bi bi-lightning-charge-fill" aria-hidden="true"></i></span><span class="small font-medium">Open API</span>
  </div>
  <div class="col-sm-4 flex gap-2 items-center">
    <span class="bg-success-subtle text-success-emphasis rounded-full inline-flex items-center justify-center text-lg" style="width:44px;height:44px"><i class="bi bi-shield-check" aria-hidden="true"></i></span><span class="small font-medium">Audit trail</span>
  </div>
  <div class="col-sm-4 flex gap-2 items-center">
    <span class="bg-danger-subtle text-danger-emphasis rounded-full inline-flex items-center justify-center text-lg" style="width:44px;height:44px"><i class="bi bi-heart-fill" aria-hidden="true"></i></span><span class="small font-medium">Open API</span>
  </div>
</div>

11Section bands

Alternating bg-body and bg-body-tertiary bands separate page sections.

The calm way to run a busy team

Thousands of customers already trust us, and we work hard to keep it that way.

Know what is happening, without asking

Every detail is handled by people who care about getting it right.

Automate the boring parts of work

Start in minutes and get help from a real person whenever you need it.

<div class="border rounded-xl overflow-hidden">
  <section class="bg-page p-6">
    <h3 class="h6 mb-1">The calm way to run a busy team</h3>
    <p class="small mb-0 text-muted">Thousands of customers already trust us, and we work hard to keep it that way.</p>
  </section>
  <section class="bg-surface-3 p-6">
    <h3 class="h6 mb-1">Know what is happening, without asking</h3>
    <p class="small mb-0 text-muted">Every detail is handled by people who care about getting it right.</p>
  </section>
  <section class="bg-page p-6">
    <h3 class="h6 mb-1">Automate the boring parts of work</h3>
    <p class="small mb-0 text-muted">Start in minutes and get help from a real person whenever you need it.</p>
  </section>
</div>

12Dark footer strip

bg-dark with text-white-50 and link-light builds a compact footer.

<footer class="bg-dark text-white/50 rounded-lg p-4 flex flex-col sm:flex-row justify-between gap-2 small">
  <span>&copy; Halo Works</span> <span class="flex gap-4"><a href="#" class="link-light">Privacy</a><a href="#" class="link-light">Terms</a><a href="#" class="link-light">Contact</a></span> 
</footer>

13Alert-like message

A message strip built from bg-danger-subtle, a matching border and emphasis text.

Payment failed. We keep things simple, so you can focus on what matters to you.

<div class="bg-danger-subtle border border-danger/30 text-danger-emphasis rounded-lg p-4 flex gap-2" role="alert">
  <span class="text-lg"><i class="bi bi-exclamation-octagon-fill" aria-hidden="true"></i></span> 
  <div>
    <strong>Payment failed.</strong> <span class="small">We keep things simple, so you can focus on what matters to you.</span>
  </div>
</div>

14Background on hoverable list

List items with bg-body-tertiary for the active one; other rows stay on bg-body.

Inbox
Starred
Sent
Archive

<ul class="list-unstyled border rounded-lg mb-0 overflow-hidden" style="max-width:20rem">
  <li class="px-4 py-2 bg-page border-b"><i class="bi bi-inbox" aria-hidden="true"></i> Inbox</li>
  <li class="px-4 py-2 bg-surface-3 border-b font-semibold"><i class="bi bi-star-fill" aria-hidden="true"></i> Starred</li>
  <li class="px-4 py-2 bg-page border-b"><i class="bi bi-send" aria-hidden="true"></i> Sent</li>
  <li class="px-4 py-2 bg-page"><i class="bi bi-archive" aria-hidden="true"></i> Archive</li>
</ul>

15Progress made from backgrounds

A bg-body-secondary track and a bg-success fill with a width utility form a simple meter.

Storage75 of 100 GB

Seats5 of 20

<div class="grid gap-4">
  <div>
    <div class="flex justify-between small mb-1">
      <span>Storage</span><span>75 of 100 GB</span>
    </div>
    <div class="bg-surface-2 rounded-full" style="height:8px">
      <div class="bg-success rounded-full h-full w-3/4">
      </div>
    </div>
  </div>
  <div>
    <div class="flex justify-between small mb-1">
      <span>Seats</span><span>5 of 20</span>
    </div>
    <div class="bg-surface-2 rounded-full" style="height:8px">
      <div class="bg-warning rounded-full h-full w-1/4">
      </div>
    </div>
  </div>
</div>

16Pricing highlight

The recommended plan gets text-bg-primary (the brand colour with the text colour that reads on it); the others stay on bg-body-tertiary.

Basic

$9.22

Pro

$33.40

Team

$77.79

<div class="row g-2 text-center">
  <div class="col-4">
    <div class="bg-surface-3 rounded-lg p-4">
      <div class="small">
        Basic
      </div>
      <div class="text-lg font-bold">
        $9.22
      </div>
    </div>
  </div>
  <div class="col-4">
    <div class="text-bg-primary rounded-lg p-4">
      <div class="small">
        Pro
      </div>
      <div class="text-lg font-bold">
        $33.40
      </div>
    </div>
  </div>
  <div class="col-4">
    <div class="bg-surface-3 rounded-lg p-4">
      <div class="small">
        Team
      </div>
      <div class="text-lg font-bold">
        $77.79
      </div>
    </div>
  </div>
</div>

17Colour swatches

Square swatches with bg-{colour} and a caption below, as used in a style guide.

Primary

Secondary

Success

Warning

Surface

<div class="flex flex-wrap gap-4">
  <figure class="mb-0 text-center">
    <div class="bg-primary rounded-lg" style="width:56px;height:56px">
    </div>
    <figcaption class="small mt-1">Primary</figcaption>
  </figure>
  <figure class="mb-0 text-center">
    <div class="bg-secondary rounded-lg" style="width:56px;height:56px">
    </div>
    <figcaption class="small mt-1">Secondary</figcaption>
  </figure>
  <figure class="mb-0 text-center">
    <div class="bg-success rounded-lg" style="width:56px;height:56px">
    </div>
    <figcaption class="small mt-1">Success</figcaption>
  </figure>
  <figure class="mb-0 text-center">
    <div class="bg-warning rounded-lg" style="width:56px;height:56px">
    </div>
    <figcaption class="small mt-1">Warning</figcaption>
  </figure>
  <figure class="mb-0 text-center">
    <div class="bg-surface-2 border rounded-lg" style="width:56px;height:56px">
    </div>
    <figcaption class="small mt-1">Surface</figcaption>
  </figure>
</div>

18Card header and footer tints

bg-body-tertiary on the header and footer of a card, bg-body in the middle.

What our customers asked us most

We listen first, then build a plan around what you actually need.

Updated 10 hours ago

<div class="border rounded-lg overflow-hidden" style="max-width:24rem">
  <div class="bg-surface-3 px-4 py-2 border-b font-semibold small">
    What our customers asked us most
  </div>
  <div class="bg-page p-4 small">
    We listen first, then build a plan around what you actually need.
  </div>
  <div class="bg-surface-3 px-4 py-2 border-t small text-muted">
    Updated 10 hours ago
  </div>
</div>

19Image scrim with bg-black

A bg-black layer at reduced --ui-bg-opacity makes white text readable over a photo.

Work that moves itself forward

<div class="relative rounded-xl overflow-hidden" style="max-width:28rem">
  <img src="https://images.unsplash.com/photo-1758691737124-05c5bffe46f0?auto=format&fit=crop&w=1600&h=700&q=70" alt="Plan, build and launch in one place" class="w-full block"> 
  <div class="absolute top-0 start-0 w-full h-full bg-black flex items-center justify-center" style="--ui-bg-opacity:.45">
    <span class="text-white text-lg font-semibold text-center px-4">Work that moves itself forward</span> 
  </div>
</div>

20Chat bubbles

Incoming messages on bg-body-tertiary, outgoing on bg-primary, each with a rounded corner set.

Our team has done this many times, so you never have to guess.

Plan projects, track progress and share updates without another status meeting.

Every update lands in one place, so nothing gets lost in email threads.

<div class="flex flex-col gap-2" style="max-width:24rem">
  <div class="self-start bg-surface-3 rounded-xl rounded-b-none px-4 py-2 small">
    Our team has done this many times, so you never have to guess.
  </div>
  <div class="self-end text-bg-primary rounded-xl rounded-b-none px-4 py-2 small">
    Plan projects, track progress and share updates without another status meeting.
  </div>
  <div class="self-start bg-surface-3 rounded-xl rounded-b-none px-4 py-2 small">
    Every update lands in one place, so nothing gets lost in email threads.
  </div>
</div>