bootstrap/scss/_toasts.scss

@keyframes scale-x-frames {
  0% {
    transform: scaleX(0);
  }
  to {
    transform: scaleX(1);
  }
}

.toast {
  // scss-docs-start toast-css-vars
  --#{$prefix}toast-padding-x: #{$toast-padding-x};
  --#{$prefix}toast-padding-y: #{$toast-padding-y};
  --#{$prefix}toast-spacing: #{$toast-spacing};
  --#{$prefix}toast-max-width: #{$toast-max-width};
  @include rfs($toast-font-size, --#{$prefix}toast-font-size);
  --#{$prefix}toast-color: #{$toast-color};
  --#{$prefix}toast-bg: #{$toast-background-color};
  --#{$prefix}toast-border-width: #{$toast-border-width};
  --#{$prefix}toast-border-color: #{$toast-border-color};
  --#{$prefix}toast-border-radius: #{$toast-border-radius};
  --#{$prefix}toast-box-shadow: #{$toast-box-shadow};
  --#{$prefix}toast-header-color: #{$toast-header-color};
  --#{$prefix}toast-header-bg: #{$toast-header-background-color};
  --#{$prefix}toast-header-border-color: #{$toast-header-border-color};
  // scss-docs-end toast-css-vars

  width: var(--#{$prefix}toast-max-width);
  max-width: 100%;
  @include font-size(var(--#{$prefix}toast-font-size));
  color: var(--#{$prefix}toast-color);
  pointer-events: auto;
  background-color: var(--#{$prefix}toast-bg);
  background-clip: padding-box;
  border: var(--#{$prefix}toast-border-width) solid var(--#{$prefix}toast-border-color);
  box-shadow: var(--#{$prefix}toast-box-shadow);
  @include border-radius(var(--#{$prefix}toast-border-radius));

  &.showing {
    opacity: 0;
  }

  &:not(.show) {
    display: none;
  }

  $toast-progress-height: 5px;
  $toast-progress-bg-color: #add555;
  $toast-progress-elapsed-bg-color: rgba(255, 255, 255, .7);
  $toast-progress-transform-origin: right;
  .toast-progress {
    position: relative;
    height: $toast-progress-height;
    background-color: $toast-progress-bg-color;

    &.animated::after {
      position: absolute;
      right: 0;
      width: 100%;
      height: 100%;
      content: "";
      background-color: $toast-progress-elapsed-bg-color;
      transform-origin: $toast-progress-transform-origin;
      animation: scale-x-frames linear 1 forwards;
      animation-duration: inherit;
    }
  }

}

.toast-container {
  position: absolute;
  z-index: $zindex-toast;
  width: max-content;
  max-width: 100%;
  pointer-events: none;

  > :not(:last-child) {
    margin-bottom: var(--#{$prefix}toast-spacing);
  }
}

.toast-header {
  display: flex;
  align-items: center;
  padding: var(--#{$prefix}toast-padding-y) var(--#{$prefix}toast-padding-x);
  color: var(--#{$prefix}toast-header-color);
  background-color: var(--#{$prefix}toast-header-bg);
  background-clip: padding-box;
  border-bottom: var(--#{$prefix}toast-border-width) solid var(--#{$prefix}toast-header-border-color);
  @include border-top-radius(calc(var(--#{$prefix}toast-border-radius) - var(--#{$prefix}toast-border-width)));

  .btn-close {
    margin-right: calc(var(--#{$prefix}toast-padding-x) * -.5); // stylelint-disable-line function-disallowed-list
    margin-left: var(--#{$prefix}toast-padding-x);
  }
}

.toast-body {
  padding: var(--#{$prefix}toast-padding-x);
  word-wrap: break-word;
}