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

Global clients

bg-dark bg-gradient

Award-winning team

<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">
        Global clients
      </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">
        Award-winning team
      </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
#INV-8458	Tariq Delgado	$118.56
#TX-6201	Ava Brennan	$236.12
#ORD-6180	Hana Patel	$397.51

<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>#INV-8458</td>
        <td>Tariq Delgado</td>
        <td class="text-end">$118.56</td>
      </tr>
      <tr>
        <td class="bg-primary-subtle">#TX-6201</td>
        <td class="bg-primary-subtle">Ava Brennan</td>
        <td class="bg-primary-subtle text-end font-semibold">$236.12</td>
      </tr>
      <tr>
        <td>#ORD-6180</td>
        <td>Hana Patel</td>
        <td class="text-end">$397.51</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.

Fast turnaround

Weekly demos

Fixed-price projects

<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">Fast turnaround</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">Weekly demos</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">Fixed-price projects</span>
  </div>
</div>

11Section bands

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

Creative work with measurable results

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

Design that earns attention

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

We design brands people remember

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

<div class="border rounded-xl overflow-hidden">
  <section class="bg-page p-6">
    <h3 class="h6 mb-1">Creative work with measurable results</h3>
    <p class="small mb-0 text-muted">Thousands of clients 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">Design that earns attention</h3>
    <p class="small mb-0 text-muted">Start in minutes and get help from a real person whenever you need it.</p>
  </section>
  <section class="bg-page p-6">
    <h3 class="h6 mb-1">We design brands people remember</h3>
    <p class="small mb-0 text-muted">Our team has done this many times, so you never have to guess.</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; Nimbus Kit</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. Clients stay with us for years because we treat their brand like our own.

<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">Clients stay with us for years because we treat their brand like our own.</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-fill" 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-fill" aria-hidden="true"></i> Sent</li>
  <li class="px-4 py-2 bg-page"><i class="bi bi-archive-fill" 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

$10.15

Pro

$33.14

Team

$58.97

<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">
        $10.15
      </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">
        $33.14
      </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">
        $58.97
      </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.

Choosing colours that sell

Websites we build are fast, accessible and easy for your team to update.

Updated 5 days 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">
    Choosing colours that sell
  </div>
  <div class="bg-page p-4 small">
    Websites we build are fast, accessible and easy for your team to update.
  </div>
  <div class="bg-surface-3 px-4 py-2 border-t small text-muted">
    Updated 5 days ago
  </div>
</div>

19Image scrim with bg-black

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

Digital products with personality

<div class="relative rounded-xl overflow-hidden" style="max-width:28rem">
  <img src="https://images.unsplash.com/photo-1742440710226-450e3b85c100?auto=format&fit=crop&w=1600&h=700&q=70" alt="Make your next launch unforgettable" 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">Digital products with personality</span> 
  </div>
</div>

20Chat bubbles

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

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

We measure success in sign-ups, sales and brand recall, not just awards.

Small teams, short feedback loops and no handoffs lost in translation.

<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">
    Clear prices, honest advice and no surprises along the way.
  </div>
  <div class="self-end text-bg-primary rounded-xl rounded-b-none px-4 py-2 small">
    We measure success in sign-ups, sales and brand recall, not just awards.
  </div>
  <div class="self-start bg-surface-3 rounded-xl rounded-b-none px-4 py-2 small">
    Small teams, short feedback loops and no handoffs lost in translation.
  </div>
</div>