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.

Better habits start this week

Community events keep you motivated, from fun runs to workshops.

<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">Better habits start this week</h3>
  <p class="small mb-0">Community events keep you motivated, from fun runs to workshops.</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="Kenji Morgan" width="44" height="44" class="rounded-circle border border-2 border-white position-relative z-3"> <img src="../assets/img/avatar-7.svg" alt="Tariq Silva" 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="Ivy Moreau" 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="Lucas Kowalski" 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.

Why recovery matters as much as training

product

<div class="position-relative rounded-4 overflow-hidden" style="max-width:20rem">
  <img src="https://images.unsplash.com/photo-1761839258420-5c3e2f2e2a74?auto=format&fit=crop&w=1200&h=800&q=70" alt="Why recovery matters as much as training" 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">product</span> 
</div>

8Floating label above a chart

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

Peak 784

<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 784</span> 
</div>

9Sticky header layer

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

Team

Liam Varga new

Samir Mensah

Noah Hughes

Isla Mensah

Leo Duarte

<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">
    Liam Varga <span class="badge text-bg-success position-relative z-1">new</span>
  </div>
  <div class="px-3 py-2 border-bottom">
    Samir Mensah
  </div>
  <div class="px-3 py-2 border-bottom">
    Noah Hughes
  </div>
  <div class="px-3 py-2 border-bottom">
    Isla Mensah
  </div>
  <div class="px-3 py-2">
    Leo Duarte
  </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.

Stronger every single day

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

<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-1583454110551-21f2fa2afe61?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">Stronger every single day</h3>
  <p class="mb-0 small">Start in minutes and get help from a real person whenever you need it.</p>
</div>

12Focus ring over siblings

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

HIIT
HIIT
HIIT

<ul class="list-unstyled mb-0" style="max-width:18rem">
  <li class="border px-3 py-2 rounded-top position-relative">HIIT</li>
  <li class="border border-primary bg-primary-subtle px-3 py-2 position-relative z-1" style="margin-top:-1px">HIIT</li>
  <li class="border px-3 py-2 rounded-bottom position-relative" style="margin-top:-1px">HIIT</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">42</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.

Recovery

29 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">
      Recovery
    </div>
    <div class="small text-body-secondary">
      29 documents
    </div>
  </div>
</div>

15Overlapping sections

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

Feel at home in your gym

Our recovery spa has a sauna, cold plunge and massage rooms.

<div>
  <div class="text-bg-primary rounded-top-4 p-4 pb-5">
    <h3 class="h5 mb-0">Feel at home in your gym</h3>
  </div>
  <div class="position-relative z-1 bg-body border rounded-4 shadow-sm p-3 mx-3" style="margin-top:-2rem">
    Our recovery spa has a sauna, cold plunge and massage rooms.
  </div>
</div>

16Corner ribbon above a border

A z-2 ribbon overlaps the card border.

Draft

Group classes

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

<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">Draft</span> 
  <div class="fw-semibold">
    Group classes
  </div>
  <div class="small text-body-secondary">
    We listen first, then build a plan around what you actually need.
  </div>
</div>

17Hover card layer (static preview)

A preview popover on z-3 overlapping a list.

Jonah Haddad
Maya Nguyen
Finn Ortega

Nutrition plans fit your routine and the food you actually enjoy.

<div class="position-relative" style="height:150px">
  <ul class="list-unstyled border rounded-3 mb-0">
    <li class="px-3 py-2 border-bottom">Jonah Haddad</li>
    <li class="px-3 py-2 border-bottom">Maya Nguyen</li>
    <li class="px-3 py-2">Finn Ortega</li>
  </ul>
  <div class="position-absolute bg-body border rounded-3 shadow p-3 z-3 small" style="top:20px;left:40%;width:13rem">
    Nutrition plans fit your routine and the food you actually enjoy.
  </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.

$92.91

<div class="position-relative rounded-4 overflow-hidden border" style="max-width:16rem">
  <img src="../assets/img/product-11.svg" alt="Bootcamp" class="w-100 d-block"> <span class="position-absolute bottom-0 start-0 m-2 badge text-bg-dark z-1">$92.91</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

Every detail is handled by people who care about getting it right. Modern equipment is cleaned, serviced and ready every day.

<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">
    Every detail is handled by people who care about getting it right. Modern equipment is cleaned, serviced and ready every day.
  </div>
</div>