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.

Help us build a kinder world

Leave a gift in your will and help future generations.

<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">Help us build a kinder world</h3>
  <p class="small mb-0">Leave a gift in your will and help future generations.</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="Kai Ortega" width="44" height="44" class="rounded-circle border border-2 border-white position-relative z-3"> <img src="../assets/img/avatar-7.svg" alt="Noah Carter" 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="Mia Ibrahim" 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="Amara Duarte" 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.

news

<div class="position-relative rounded-4 overflow-hidden" style="max-width:20rem">
  <img src="https://images.unsplash.com/photo-1758599668356-c8c919e24dda?auto=format&fit=crop&w=1200&h=800&q=70" alt="Our favourite tips for busy weeks" 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">news</span> 
</div>

8Floating label above a chart

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

Peak 865

<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 865</span> 
</div>

9Sticky header layer

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

Team

Ethan Rossi new

Hana Patel

Ava Okafor

Nora Harlow

Priya Ibrahim

<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">
    Ethan Rossi <span class="badge text-bg-success position-relative z-1">new</span>
  </div>
  <div class="px-3 py-2 border-bottom">
    Hana Patel
  </div>
  <div class="px-3 py-2 border-bottom">
    Ava Okafor
  </div>
  <div class="px-3 py-2 border-bottom">
    Nora Harlow
  </div>
  <div class="px-3 py-2">
    Priya Ibrahim
  </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.

Together we can change lives

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

<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-1758599668429-121d54188b9c?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">Together we can change lives</h3>
  <p class="mb-0 small">We have helped more than two hundred thousand people since we started.</p>
</div>

12Focus ring over siblings

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

Animals
Education
Relief

<ul class="list-unstyled mb-0" style="max-width:18rem">
  <li class="border px-3 py-2 rounded-top position-relative">Animals</li>
  <li class="border border-primary bg-primary-subtle px-3 py-2 position-relative z-1" style="margin-top:-1px">Education</li>
  <li class="border px-3 py-2 rounded-bottom position-relative" style="margin-top:-1px">Relief</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">64</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

18 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">
      18 documents
    </div>
  </div>
</div>

15Overlapping sections

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

Be part of the change

Clean water wells are built with and maintained by local communities.

<div>
  <div class="text-bg-primary rounded-top-4 p-4 pb-5">
    <h3 class="h5 mb-0">Be part of the change</h3>
  </div>
  <div class="position-relative z-1 bg-body border rounded-4 shadow-sm p-3 mx-3" style="margin-top:-2rem">
    Clean water wells are built with and maintained by local communities.
  </div>
</div>

16Corner ribbon above a border

A z-2 ribbon overlaps the card border.

In review

Animal rescue

Monthly gifts let us plan ahead and respond quickly when disaster strikes.

<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">In review</span> 
  <div class="fw-semibold">
    Animal rescue
  </div>
  <div class="small text-body-secondary">
    Monthly gifts let us plan ahead and respond quickly when disaster strikes.
  </div>
</div>

17Hover card layer (static preview)

A preview popover on z-3 overlapping a list.

Lea Ortega
Ravi Alvarez
Sofia Carter

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

<div class="position-relative" style="height:150px">
  <ul class="list-unstyled border rounded-3 mb-0">
    <li class="px-3 py-2 border-bottom">Lea Ortega</li>
    <li class="px-3 py-2 border-bottom">Ravi Alvarez</li>
    <li class="px-3 py-2">Sofia Carter</li>
  </ul>
  <div class="position-absolute bg-body border rounded-3 shadow p-3 z-3 small" style="top:20px;left:40%;width:13rem">
    Every detail is handled by people who care about getting it right.
  </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.

$42.27

<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">$42.27</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

Clear prices, honest advice and no surprises along the way. Volunteers give their time in schools, shelters and food banks every week.

<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">
    Clear prices, honest advice and no surprises along the way. Volunteers give their time in schools, shelters and food banks every week.
  </div>
</div>