Z-index

Z-index utilities change the stacking order of positioned elements: z-n1 sends an element behind its context, z-0 creates a base layer and z-1, z-2 and z-3 bring elements forward. They only apply to elements with a position, so pair them with position-relative or position-absolute.

1Z-index scale

z-n1, z-0, z-1, z-2 and z-3 stack positioned elements from back to front.

z-3

z-2

z-1

z-0

z-n1

<div class="position-relative" style="height:170px">
  <div class="position-absolute rounded-3 p-2 small fw-semibold border bg-body-secondary z-3" style="top:0;left:0;width:150px;height:90px">
    z-3
  </div>
  <div class="position-absolute rounded-3 p-2 small fw-semibold border bg-primary-subtle z-2" style="top:20px;left:40px;width:150px;height:90px">
    z-2
  </div>
  <div class="position-absolute rounded-3 p-2 small fw-semibold border bg-success-subtle z-1" style="top:40px;left:80px;width:150px;height:90px">
    z-1
  </div>
  <div class="position-absolute rounded-3 p-2 small fw-semibold border bg-warning-subtle z-0" style="top:60px;left:120px;width:150px;height:90px">
    z-0
  </div>
  <div class="position-absolute rounded-3 p-2 small fw-semibold border bg-danger-subtle z-n1" style="top:80px;left:160px;width:150px;height:90px">
    z-n1
  </div>
</div>

2Order without z-index

Without z-index, later elements paint on top of earlier ones.

first

second (on top)

<div class="position-relative" style="height:130px">
  <div class="position-absolute rounded-3 p-2 small fw-semibold border bg-primary-subtle" style="top:0;left:0;width:160px;height:90px">
    first
  </div>
  <div class="position-absolute rounded-3 p-2 small fw-semibold border bg-info-subtle" style="top:30px;left:60px;width:160px;height:90px">
    second (on top)
  </div>
</div>

3Bring the first one forward

z-1 on the first element puts it above its later sibling.

first, z-1

second

<div class="position-relative" style="height:130px">
  <div class="position-absolute rounded-3 p-2 small fw-semibold border bg-primary-subtle z-1" style="top:0;left:0;width:160px;height:90px">
    first, z-1
  </div>
  <div class="position-absolute rounded-3 p-2 small fw-semibold border bg-info-subtle" style="top:30px;left:60px;width:160px;height:90px">
    second
  </div>
</div>

4Background shape behind content

z-n1 places a decorative shape behind the text of its positioned parent, which uses z-0 to form a stacking context.

Stand with families in need

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

<div class="position-relative z-0 p-4">
  <div class="position-absolute top-0 start-0 bg-primary-subtle rounded-circle z-n1" style="width:120px;height:120px">
  </div>
  <h3 class="h5 fw-semibold">Stand with families in need</h3>
  <p class="small mb-0">A school kit costs less than a cinema ticket and lasts a whole year.</p>
</div>

5Overlapping avatars

Decreasing z-index keeps the first avatar on top of the stack.

<div class="d-flex">
  <img src="../assets/img/avatar-6.svg" alt="Sofia Mensah" width="44" height="44" class="rounded-circle border border-2 border-white position-relative z-3"> <img src="../assets/img/avatar-7.svg" alt="Ella Larsen" width="44" height="44" class="rounded-circle border border-2 border-white position-relative z-2" style="margin-left:-14px"> <img src="../assets/img/avatar-8.svg" alt="Freya Whitaker" width="44" height="44" class="rounded-circle border border-2 border-white position-relative z-1" style="margin-left:-14px"> <img src="../assets/img/avatar-9.svg" alt="Elena Lindqvist" width="44" height="44" class="rounded-circle border border-2 border-white position-relative z-0" style="margin-left:-14px"> 
</div>

6Active button above its neighbours

In joined button rows the active one gets z-1 so its border is not hidden.

<div class="d-flex">
  <button type="button" class="btn btn-outline-secondary rounded-0 rounded-start position-relative">Day</button>
  <button type="button" class="btn btn-outline-primary rounded-0 position-relative z-1 active" style="margin-left:-1px" aria-pressed="true">Week</button>
  <button type="button" class="btn btn-outline-secondary rounded-0 rounded-end position-relative" style="margin-left:-1px">Month</button>
</div>

7Badge over a card image

The badge uses z-2 so it stays above an overlay with z-1.

design

<div class="position-relative rounded-4 overflow-hidden" style="max-width:20rem">
  <img src="https://images.unsplash.com/photo-1758599668178-d9716bbda9d5?auto=format&fit=crop&w=1200&h=800&q=70" alt="Looking back at a busy season" class="w-100 d-block"> 
  <div class="position-absolute top-0 start-0 w-100 h-100 bg-dark bg-opacity-25 z-1">
  </div>
  <span class="position-absolute top-0 start-0 m-2 badge text-bg-warning z-2">design</span> 
</div>

8Floating label above a chart

A z-3 label stays above grid lines and bars.

Peak 472

<div class="position-relative border rounded-3 p-3" style="height:150px">
  <div class="position-absolute start-0 end-0 border-top z-0" style="top:50px">
  </div>
  <div class="position-absolute start-0 end-0 border-top z-0" style="top:100px">
  </div>
  <div class="d-flex align-items-end gap-2 h-100 position-relative z-1">
    <div class="bg-primary-subtle flex-fill h-50 rounded-top">
    </div>
    <div class="bg-primary flex-fill h-75 rounded-top">
    </div>
    <div class="bg-primary-subtle flex-fill h-25 rounded-top">
    </div>
  </div>
  <span class="position-absolute top-0 start-50 translate-middle-x mt-2 badge text-bg-dark z-3">Peak 472</span> 
</div>

9Sticky header layer

A sticky header with z-2 stays above rows that have their own positioned badges.

Team

Amara Sato new

Ruby Ortega

Priya Moreau

Omar Ortega

Finn Hughes

<div class="border rounded-3 overflow-auto" style="height:160px">
  <div class="sticky-top z-2 bg-body-secondary px-3 py-2 small fw-semibold">
    Team
  </div>
  <div class="px-3 py-2 border-bottom position-relative">
    Amara Sato <span class="badge text-bg-success position-relative z-1">new</span>
  </div>
  <div class="px-3 py-2 border-bottom">
    Ruby Ortega
  </div>
  <div class="px-3 py-2 border-bottom">
    Priya Moreau
  </div>
  <div class="px-3 py-2 border-bottom">
    Omar Ortega
  </div>
  <div class="px-3 py-2">
    Finn Hughes
  </div>
</div>

10Cards in a fan

Rotated cards stacked with z-1 to z-3.

z-1

z-2

z-3

<div class="position-relative mx-auto" style="height:170px;max-width:18rem">
  <div class="position-absolute top-50 start-50 bg-body border rounded-3 shadow-sm p-3 z-1" style="width:140px;transform:translate(-80%,-50%) rotate(-10deg)">
    <div class="small">
      <code class="small">z-1</code>
    </div>
  </div>
  <div class="position-absolute top-50 start-50 bg-body border rounded-3 shadow-sm p-3 z-2" style="width:140px;transform:translate(-50%,-50%)">
    <div class="small">
      <code class="small">z-2</code>
    </div>
  </div>
  <div class="position-absolute top-50 start-50 bg-body border rounded-3 shadow-sm p-3 z-3" style="width:140px;transform:translate(-20%,-50%) rotate(10deg)">
    <div class="small fw-bold">
      <code class="small">z-3</code>
    </div>
  </div>
</div>

11Image behind a heading

The hero image sits on z-n1 inside a z-0 context, the text sits on top.

Help us build a kinder world

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

<div class="position-relative z-0 rounded-4 overflow-hidden p-4 text-white bg-dark" style="min-height:180px">
  <img src="https://images.unsplash.com/photo-1706806595136-5afefb45da1a?auto=format&fit=crop&w=1600&h=700&q=70" alt="" class="position-absolute top-0 start-0 w-100 h-100 object-fit-cover z-n1"> 
  <div class="position-absolute top-0 start-0 w-100 h-100 bg-dark bg-opacity-50 z-n1">
  </div>
  <h3 class="h4 fw-bold">Help us build a kinder world</h3>
  <p class="mb-0 small">Clear prices, honest advice and no surprises along the way.</p>
</div>

12Focus ring over siblings

List group items lift their active item with z-1 so its border shows on both edges.

Environment
Animals
Environment

<ul class="list-unstyled mb-0" style="max-width:18rem">
  <li class="border px-3 py-2 rounded-top position-relative">Environment</li>
  <li class="border border-primary bg-primary-subtle px-3 py-2 position-relative z-1" style="margin-top:-1px">Animals</li>
  <li class="border px-3 py-2 rounded-bottom position-relative" style="margin-top:-1px">Environment</li>
</ul>

13Notification over a header

A count badge on z-3 overlaps the next header item.

<div class="d-flex gap-3 border rounded-3 p-3 align-items-center">
  <span class="position-relative fs-4"><i class="bi bi-bell-fill" aria-hidden="true"></i><span class="position-absolute top-0 start-100 translate-middle badge rounded-pill text-bg-danger z-3 fs-6">91</span></span> <span class="position-relative fs-4 bg-body rounded-2 px-2"><i class="bi bi-chat-dots-fill" aria-hidden="true"></i></span> 
</div>

14Stacked paper effect

Two layers on z-n1 behind a card look like a pile of pages.

Environment

11 documents

<div class="position-relative z-0 mx-auto" style="max-width:20rem">
  <div class="position-absolute top-0 start-0 w-100 h-100 bg-body-secondary border rounded-3 z-n1" style="transform:translate(8px,8px)">
  </div>
  <div class="position-absolute top-0 start-0 w-100 h-100 bg-body-tertiary border rounded-3 z-n1" style="transform:translate(4px,4px)">
  </div>
  <div class="bg-body border rounded-3 p-3">
    <div class="fw-semibold">
      Environment
    </div>
    <div class="small text-body-secondary">
      11 documents
    </div>
  </div>
</div>

15Overlapping sections

A card with z-1 overlaps the coloured band above it via a negative top offset.

Your kindness travels further than you think

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

<div>
  <div class="text-bg-primary rounded-top-4 p-4 pb-5">
    <h3 class="h5 mb-0">Your kindness travels further than you think</h3>
  </div>
  <div class="position-relative z-1 bg-body border rounded-4 shadow-sm p-3 mx-3" style="margin-top:-2rem">
    Every detail is handled by people who care about getting it right.
  </div>
</div>

16Corner ribbon above a border

A z-2 ribbon overlaps the card border.

Completed

Clean water

Friendly people answer your questions quickly, by phone, chat or email.

<div class="position-relative border border-2 rounded-4 p-4" style="max-width:18rem">
  <span class="position-absolute top-0 end-0 translate-middle-y me-3 badge text-bg-success z-2">Completed</span> 
  <div class="fw-semibold">
    Clean water
  </div>
  <div class="small text-body-secondary">
    Friendly people answer your questions quickly, by phone, chat or email.
  </div>
</div>

17Hover card layer (static preview)

A preview popover on z-3 overlapping a list.

Zoe Delgado
Jonah Larsen
Arjun Kim

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

<div class="position-relative" style="height:150px">
  <ul class="list-unstyled border rounded-3 mb-0">
    <li class="px-3 py-2 border-bottom">Zoe Delgado</li>
    <li class="px-3 py-2 border-bottom">Jonah Larsen</li>
    <li class="px-3 py-2">Arjun Kim</li>
  </ul>
  <div class="position-absolute bg-body border rounded-3 shadow p-3 z-3 small" style="top:20px;left:40%;width:13rem">
    Thousands of donors already trust us, and we work hard to keep it that way.
  </div>
</div>

18Z-index needs a position

z-* only works on positioned elements: the left box has no position, the right one has position-relative.

z-3, static (ignored)

z-3, position-relative

<div class="row g-2">
  <div class="col-6">
    <div class="bg-info-subtle border rounded-3 p-3 z-3 small">
      z-3, static (ignored)
    </div>
  </div>
  <div class="col-6">
    <div class="bg-info-subtle border rounded-3 p-3 z-3 position-relative small">
      z-3, position-relative
    </div>
  </div>
</div>

19Price tag over a product

A z-1 price tag over the product image and a z-2 heart button above it.

$59.02

<div class="position-relative rounded-4 overflow-hidden border" style="max-width:16rem">
  <img src="../assets/img/product-11.svg" alt="Solar lamp" class="w-100 d-block"> <span class="position-absolute bottom-0 start-0 m-2 badge text-bg-dark z-1">$59.02</span> 
  <button type="button" class="btn btn-light btn-sm rounded-circle position-absolute top-0 end-0 m-2 z-2" aria-label="Save"><i class="bi bi-heart-fill" aria-hidden="true"></i></button>
</div>

20Dropdown above content

An open menu at z-3 overlaps the panel below it.

Newest
Price low to high
Rating

Volunteers give their time in schools, shelters and food banks every week. We have helped more than two hundred thousand people since we started.

<div class="position-relative" style="height:170px">
  <button type="button" class="btn btn-sm btn-outline-secondary"><i class="bi bi-sort-down" aria-hidden="true"></i> Sort</button>
  <ul class="position-absolute list-unstyled bg-body border rounded-3 shadow py-1 mt-1 z-3 small mb-0" style="width:11rem">
    <li class="px-3 py-1">Newest</li>
    <li class="px-3 py-1 bg-primary-subtle">Price low to high</li>
    <li class="px-3 py-1">Rating</li>
  </ul>
  <div class="bg-body-tertiary border rounded-3 p-3 mt-2 small">
    Volunteers give their time in schools, shelters and food banks every week. We have helped more than two hundred thousand people since we started.
  </div>
</div>