View on GitHub

Borders

Use border utilities to quickly style the border and border-radius of an element. Great for images, buttons, or any other element.

On this page

Border

Use border utilities to add or remove an element’s borders. Choose from all borders or one at a time.

Additive

Add borders to custom elements:

html

<span class="border"></span>
<span class="border-top"></span>
<span class="border-end"></span>
<span class="border-bottom"></span>
<span class="border-start"></span>

Subtractive

Or remove borders:

html

<span class="border border-0"></span>
<span class="border border-top-0"></span>
<span class="border border-end-0"></span>
<span class="border border-bottom-0"></span>
<span class="border border-start-0"></span>

Color

Change the border color using utilities built on our theme colors.

html

<span class="border border-primary"></span>
<span class="border border-secondary"></span>
<span class="border border-success"></span>
<span class="border border-danger"></span>
<span class="border border-warning"></span>
<span class="border border-info"></span>
<span class="border border-light"></span>
<span class="border border-dark"></span>
<span class="border border-white"></span>

Or modify the default border-color of a component:

Email address

Dangerous heading

Changing border color and width

html

<div class="mb-4">
  <label for="exampleFormControlInput1" class="form-label">Email address</label>
  <input type="email" class="form-control border-success" id="exampleFormControlInput1" placeholder="name@example.com">
</div>

<div class="h4 pb-2 mb-4 text-danger border-bottom border-danger">
  Dangerous heading
</div>

<div class="p-3 bg-info bg-opacity-10 border border-info border-start-0 rounded-end text-body">
  Changing border color and width
</div>

Opacity

Boosted Innovation Cup border-{color} utilities are generated with Sass using CSS variables. This allows for real-time color changes without compilation and dynamic alpha transparency changes.

How it works

Consider our default .border-success utility.

.border-success {
  --bs-border-opacity: 1;
  border-color: rgba(var(--bs-success-rgb), var(--bs-border-opacity)) !important;
}

We use an RGB version of our --bs-success (with the value of 25, 135, 84) CSS variable and attached a second CSS variable, --bs-border-opacity, for the alpha transparency (with a default value 1 thanks to a local CSS variable). That means anytime you use .border-success now, your computed color value is rgba(25, 135, 84, 1). The local CSS variable inside each .border-* class avoids inheritance issues so nested instances of the utilities don’t automatically have a modified alpha transparency.

Example

To change that opacity, override --bs-border-opacity via custom styles or inline styles.

This is default success border

This is 50% opacity success border

html

<div class="border border-success p-2 mb-2">This is default success border</div>
<div class="border border-success p-2" style="--bs-border-opacity: .5;">This is 50% opacity success border</div>

Or, choose from any of the .border-opacity utilities:

This is default success border

This is 75% opacity success border

This is 50% opacity success border

This is 25% opacity success border

This is 10% opacity success border

html

<div class="border border-success p-2 mb-2">This is default success border</div>
<div class="border border-success p-2 mb-2 border-opacity-75">This is 75% opacity success border</div>
<div class="border border-success p-2 mb-2 border-opacity-50">This is 50% opacity success border</div>
<div class="border border-success p-2 mb-2 border-opacity-25">This is 25% opacity success border</div>
<div class="border border-success p-2 border-opacity-10">This is 10% opacity success border</div>

Width

html

<span class="border border-0"></span>
<span class="border border-1"></span>
<span class="border border-2"></span>
<span class="border border-3"></span>

Radius

Add classes to an element to easily round its corners.

html

<img src="..." class="rounded-circle" alt="...">
<img src="..." class="rounded-pill" alt="...">

Dividers

html

<div class="bg-dark p-1">
  <div class="border-top border-white my-3"></div>
  <hr>
</div>
<div class="border-top border-light my-3"></div>
<div class="border-top border-light border-1 my-3"></div>
<div class="border-top border-dark my-3"></div>
<div class="border-top border-dark border-1 my-3"></div>
<div class="border-top my-3"></div>
<hr class="text-light">
<hr class="text-muted">
<hr>

CSS

Variables

  --#{$prefix}border-width: #{$border-width};
  --#{$prefix}border-style: #{$border-style};
  --#{$prefix}border-color: #{$border-color};
  --#{$prefix}border-color-translucent: #{$border-color-translucent};

  --#{$prefix}border-radius: #{$border-radius};
  --#{$prefix}border-radius-sm: #{$border-radius-sm};
  --#{$prefix}border-radius-lg: #{$border-radius-lg};
  --#{$prefix}border-radius-xl: #{$border-radius-xl};
  --#{$prefix}border-radius-2xl: #{$border-radius-2xl};
  --#{$prefix}border-radius-pill: #{$border-radius-pill};

Sass variables

$border-width:                .125rem;
$border-widths: (
  1: $border-width * .5,
  2: $border-width,
  3: $border-width * 1.5
);

$border-style:                solid;
$border-color:                $black; // Boosted mod
$border-color-translucent:    $gray-500; // Boosted mod: gray value instead of rgba($black, .175)

// Boosted mod: all `$border-radius*` values are `null`
$border-radius:               null;
$border-radius-sm:            null;
$border-radius-lg:            null;
$border-radius-xl:            null;
$border-radius-2xl:           null;
// End mod
$border-radius-pill:          50rem;

Sass mixins

@mixin border-radius($radius: $border-radius, $fallback-border-radius: false) {
  @if $enable-rounded {
    border-radius: valid-radius($radius);
  }
  @else if $fallback-border-radius != false {
    border-radius: $fallback-border-radius;
  }
}

@mixin border-top-radius($radius: $border-radius) {
  @if $enable-rounded {
    border-top-left-radius: valid-radius($radius);
    border-top-right-radius: valid-radius($radius);
  }
}

@mixin border-end-radius($radius: $border-radius) {
  @if $enable-rounded {
    border-top-right-radius: valid-radius($radius);
    border-bottom-right-radius: valid-radius($radius);
  }
}

@mixin border-bottom-radius($radius: $border-radius) {
  @if $enable-rounded {
    border-bottom-right-radius: valid-radius($radius);
    border-bottom-left-radius: valid-radius($radius);
  }
}

@mixin border-start-radius($radius: $border-radius) {
  @if $enable-rounded {
    border-top-left-radius: valid-radius($radius);
    border-bottom-left-radius: valid-radius($radius);
  }
}

@mixin border-top-start-radius($radius: $border-radius) {
  @if $enable-rounded {
    border-top-left-radius: valid-radius($radius);
  }
}

@mixin border-top-end-radius($radius: $border-radius) {
  @if $enable-rounded {
    border-top-right-radius: valid-radius($radius);
  }
}

@mixin border-bottom-end-radius($radius: $border-radius) {
  @if $enable-rounded {
    border-bottom-right-radius: valid-radius($radius);
  }
}

@mixin border-bottom-start-radius($radius: $border-radius) {
  @if $enable-rounded {
    border-bottom-left-radius: valid-radius($radius);
  }
}

Utilities API

Border utilities are declared in our utilities API in scss/_utilities.scss. Learn how to use the utilities API.

    "border": (
      property: border,
      values: (
        null: var(--#{$prefix}border-width) var(--#{$prefix}border-style) var(--#{$prefix}border-color),
        0: 0,
      )
    ),
    "border-top": (
      property: border-top,
      values: (
        null: var(--#{$prefix}border-width) var(--#{$prefix}border-style) var(--#{$prefix}border-color),
        0: 0,
      )
    ),
    "border-end": (
      property: border-right,
      class: border-end,
      values: (
        null: var(--#{$prefix}border-width) var(--#{$prefix}border-style) var(--#{$prefix}border-color),
        0: 0,
      )
    ),
    "border-bottom": (
      property: border-bottom,
      values: (
        null: var(--#{$prefix}border-width) var(--#{$prefix}border-style) var(--#{$prefix}border-color),
        0: 0,
      )
    ),
    "border-start": (
      property: border-left,
      class: border-start,
      values: (
        null: var(--#{$prefix}border-width) var(--#{$prefix}border-style) var(--#{$prefix}border-color),
        0: 0,
      )
    ),
    "border-color": (
      property: border-color,
      class: border,
      local-vars: (
        "border-opacity": 1
      ),
      values: $utilities-border-colors
    ),
    "border-width": (
      css-var: true,
      css-variable-name: border-width,
      class: border,
      values: $border-widths
    ),
    "border-opacity": (
      css-var: true,
      class: border-opacity,
      values: (
        10: .1,
        25: .25,
        50: .5,
        75: .75,
        100: 1
      )
    ),

    "rounded": (
      property: border-radius,
      class: rounded,
      values: (
        null: var(--#{$prefix}border-radius),
        0: 0,
        1: var(--#{$prefix}border-radius-sm),
        2: var(--#{$prefix}border-radius),
        3: var(--#{$prefix}border-radius-lg),
        4: var(--#{$prefix}border-radius-xl),
        5: var(--#{$prefix}border-radius-2xl),
        circle: 50%,
        pill: var(--#{$prefix}border-radius-pill)
      )
    ),
    "rounded-top": (
      property: border-top-left-radius border-top-right-radius,
      class: rounded-top,
      values: (null: var(--#{$prefix}border-radius))
    ),
    "rounded-end": (
      property: border-top-right-radius border-bottom-right-radius,
      class: rounded-end,
      values: (null: var(--#{$prefix}border-radius))
    ),
    "rounded-bottom": (
      property: border-bottom-right-radius border-bottom-left-radius,
      class: rounded-bottom,
      values: (null: var(--#{$prefix}border-radius))
    ),
    "rounded-start": (
      property: border-bottom-left-radius border-top-left-radius,
      class: rounded-start,
      values: (null: var(--#{$prefix}border-radius))
    ),