bootstrap/scss/_offcanvas.scss

@use "sass:map";
@use "config" as *;
@use "variables" as *;
@use "mixins/box-shadow" as *;
@use "mixins/transition" as *;
@use "mixins/backdrop" as *;
@use "layout/breakpoints" as *;

%offcanvas-css-vars {
  // scss-docs-start offcanvas-css-vars
  --#{$prefix}offcanvas-zindex: #{$zindex-offcanvas};
  --#{$prefix}offcanvas-width: #{$offcanvas-horizontal-width};
  --#{$prefix}offcanvas-height: #{$offcanvas-vertical-height};
  --#{$prefix}offcanvas-padding-x: #{$offcanvas-padding-x};
  --#{$prefix}offcanvas-padding-y: #{$offcanvas-padding-y};
  --#{$prefix}offcanvas-color: #{$offcanvas-color};
  --#{$prefix}offcanvas-bg: #{$offcanvas-bg-color};
  --#{$prefix}offcanvas-border-width: #{$offcanvas-border-width};
  --#{$prefix}offcanvas-border-color: #{$offcanvas-border-color};
  --#{$prefix}offcanvas-box-shadow: #{$offcanvas-box-shadow};
  --#{$prefix}offcanvas-transition: #{transform $offcanvas-transition-duration ease-in-out};
  --#{$prefix}offcanvas-title-line-height: #{$offcanvas-title-line-height};
  // scss-docs-end offcanvas-css-vars
}

@layer components {
  @each $breakpoint in map.keys($grid-breakpoints) {
    $next: breakpoint-next($breakpoint, $grid-breakpoints);
    $infix: breakpoint-infix($next, $grid-breakpoints);

    .offcanvas#{$infix} {
      @extend %offcanvas-css-vars;
    }
  }

  @each $breakpoint in map.keys($grid-breakpoints) {
    $next: breakpoint-next($breakpoint, $grid-breakpoints);
    $infix: breakpoint-infix($next, $grid-breakpoints);

    .offcanvas#{$infix} {
      @include media-breakpoint-down($next) {
        position: fixed;
        bottom: 0;
        z-index: var(--#{$prefix}offcanvas-zindex);
        display: flex;
        flex-direction: column;
        max-width: 100%;
        color: var(--#{$prefix}offcanvas-color);
        visibility: hidden;
        background-color: var(--#{$prefix}offcanvas-bg);
        background-clip: padding-box;
        outline: 0;
        @include box-shadow(var(--#{$prefix}offcanvas-box-shadow));
        @include transition(var(--#{$prefix}offcanvas-transition));

        &.offcanvas-start {
          top: 0;
          left: 0;
          width: var(--#{$prefix}offcanvas-width);
          border-right: var(--#{$prefix}offcanvas-border-width) solid var(--#{$prefix}offcanvas-border-color);
          transform: translateX(-100%);
        }

        &.offcanvas-end {
          top: 0;
          right: 0;
          width: var(--#{$prefix}offcanvas-width);
          border-left: var(--#{$prefix}offcanvas-border-width) solid var(--#{$prefix}offcanvas-border-color);
          transform: translateX(100%);
        }

        &.offcanvas-top {
          top: 0;
          right: 0;
          left: 0;
          height: var(--#{$prefix}offcanvas-height);
          max-height: 100%;
          border-bottom: var(--#{$prefix}offcanvas-border-width) solid var(--#{$prefix}offcanvas-border-color);
          transform: translateY(-100%);
        }

        &.offcanvas-bottom {
          right: 0;
          left: 0;
          height: var(--#{$prefix}offcanvas-height);
          max-height: 100%;
          border-top: var(--#{$prefix}offcanvas-border-width) solid var(--#{$prefix}offcanvas-border-color);
          transform: translateY(100%);
        }

        &.showing,
        &.show:not(.hiding) {
          transform: none;
        }

        &.showing,
        &.hiding,
        &.show {
          visibility: visible;
        }
      }

      @if not ($infix == "") {
        @include media-breakpoint-up($next) {
          --#{$prefix}offcanvas-height: auto;
          --#{$prefix}offcanvas-border-width: 0;
          background-color: transparent !important; // stylelint-disable-line declaration-no-important

          .offcanvas-header {
            display: none;
          }

          .offcanvas-body {
            display: flex;
            flex-grow: 0;
            padding: 0;
            overflow-y: visible;
            // Reset `background-color` in case `.bg-*` classes are used in offcanvas
            background-color: transparent !important; // stylelint-disable-line declaration-no-important
          }
        }
      }
    }
  }

  .offcanvas-backdrop {
    @include overlay-backdrop($zindex-offcanvas-backdrop, $offcanvas-backdrop-bg, $offcanvas-backdrop-opacity);
  }

  .offcanvas-header {
    display: flex;
    align-items: center;
    padding: var(--#{$prefix}offcanvas-padding-y) var(--#{$prefix}offcanvas-padding-x);

    .btn-close {
      padding: calc(var(--#{$prefix}offcanvas-padding-y) * .5) calc(var(--#{$prefix}offcanvas-padding-x) * .5);
      // Split properties to avoid invalid calc() function if value is 0
      margin-top: calc(-.5 * var(--#{$prefix}offcanvas-padding-y));
      margin-right: calc(-.5 * var(--#{$prefix}offcanvas-padding-x));
      margin-bottom: calc(-.5 * var(--#{$prefix}offcanvas-padding-y));
      margin-left: auto;
    }
  }

  .offcanvas-title {
    margin-bottom: 0;
    line-height: var(--#{$prefix}offcanvas-title-line-height);
  }

  .offcanvas-body {
    flex-grow: 1;
    padding: var(--#{$prefix}offcanvas-padding-y) var(--#{$prefix}offcanvas-padding-x);
    overflow-y: auto;
  }
}