$panel-spacer:                       .75rem !default;
$panel-spacer-y:                     .75rem !default;
$panel-spacer-x:                     1.25rem !default;
$panel-border-width:                 $border-width !default;
$panel-border-radius:                $border-radius !default;
$panel-border-color:                 $card-border-color;
$panel-inner-border-radius:          calc(#{$panel-border-radius} - #{$panel-border-width}) !default;
$panel-cap-bg:                       $card-cap-bg;
$panel-bg:                           $card-bg;

$panel-img-overlay-padding:          1.25rem !default;

$panel-group-margin:                 calc($panel-spacer/2) !default;
$panel-deck-margin:                  $panel-group-margin !default;

$panel-columns-count:                3 !default;
$panel-columns-gap:                  1.25rem !default;
$panel-columns-margin:               $panel-spacer-y !default;

.panel {
  margin: 0;
  padding: 0;
  position: relative;
  display: flex;
  flex-direction: column;
  min-width: 0;
  word-wrap: break-word;
  background-color: $panel-bg;
  background-clip: border-box;
  border: $panel-border-width solid $panel-border-color;
  @include border-radius($panel-border-radius);

  > hr {
    margin-right: 0;
    margin-left: 0;
  }

  > .list-group:first-child {
    .list-group-item:first-child {
      @include border-top-radius($panel-border-radius);
    }
  }

  > .list-group:last-child {
    .list-group-item:last-child {
      @include border-bottom-radius($panel-border-radius);
    }
  }

  // Select all panel toolbar except the first
  > .panel-toolbar ~ .panel-toolbar {
    border-top: $panel-border-width solid $panel-border-color;
    border-bottom: $panel-border-width solid $panel-border-color;
  }

  // Select first panel-toolbar
  > .panel-toolbar {
    border-top: none;
    padding: $panel-spacer;
    background-color: $panel-cap-bg;
    border-bottom: $panel-border-width solid $panel-border-color;
  }

  > .panel-toolbar ~ .panel-toolbar {
    border-bottom: none !important;
  }
  // Select last panel-toolbar

}

.panel-body {
  // Enable `flex-grow: 1` for decks and groups so that panel blocks take up
  // as much space as possible, ensuring footers are aligned to the bottom.
  flex: 1 1 auto;
  padding: $panel-spacer;
}

.panel-title {
  margin-bottom: $panel-spacer-y;
}

.panel-subtitle {
  margin-top: -(calc($panel-spacer-y / 2));
  margin-bottom: 0;
}

.panel-text:last-child {
  margin-bottom: 0;
}

.panel-link {
  &:hover {
    text-decoration: none;
  }

  + .panel-link {
    margin-left: $panel-spacer-x;
  }
}

//
// Optional textual caps
//

.panel-header {
  padding: $panel-spacer;
  margin-bottom: 0; // Removes the default margin-bottom of <hN>
  background-color: $panel-cap-bg;
  border-bottom: $panel-border-width solid $panel-border-color;
  display: flex;

  > div:not(.dropdown) {
    position: relative;
    display: inline-flex;
    vertical-align: middle;
  }

  &:first-child {
    @include border-radius($panel-inner-border-radius $panel-inner-border-radius 0 0);
  }

  + .list-group {
    .list-group-item:first-child {
      border-top: 0;
    }
  }

  .panel-title {
    padding: 0;
    margin: 0;
  }
}


.panel-footer {
  padding: $panel-spacer-y;
  background-color: $panel-cap-bg;
  border-top: $panel-border-width solid $panel-border-color;

  &:last-child {
    @include border-radius(0 0 $panel-inner-border-radius $panel-inner-border-radius);
  }
}

.panel-toolbar .btn-toolbar{
  margin: 0;
}

//
// Header navs
//

.panel-header-tabs {
  margin-right: -(calc($panel-spacer-x / 2));
  margin-bottom: -$panel-spacer-y;
  margin-left: 0;
  border-bottom: 0;
}

.panel-header-pills {
  margin-right: -(calc($panel-spacer-x / 2));
  margin-left: -(calc($panel-spacer-x / 2));
}

// panel image
.panel-img-overlay {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  padding: $panel-img-overlay-padding;
}

.panel-img {
  width: 100%; // Required because we use flexbox and this inherently applies align-self: stretch
  @include border-radius($panel-inner-border-radius);
}

// panel image caps
.panel-img-top {
  width: 100%; // Required because we use flexbox and this inherently applies align-self: stretch
  @include border-top-radius($panel-inner-border-radius);
}

.panel-img-bottom {
  width: 100%; // Required because we use flexbox and this inherently applies align-self: stretch
  @include border-bottom-radius($panel-inner-border-radius);
}


// panel deck

.panel-deck {
  display: flex;
  padding: $panel-spacer;
  flex-direction: column;

  & > .panel {
    margin-bottom: $panel-deck-margin;
  }

  @include media-breakpoint-up(sm) {
    flex-flow: row wrap;
    margin-right: -$panel-deck-margin;
    margin-left: -$panel-deck-margin;

    & > .panel {
      display: flex;
      // Flexbugs #4: https://github.com/philipwalton/flexbugs#4-flex-shorthand-declarations-with-unitless-flex-basis-values-are-ignored
      flex: 1 0 0%;
      flex-direction: column;
      margin-right: $panel-deck-margin;
      margin-bottom: 0; // Override the default
      margin-left: $panel-deck-margin;
    }
  }
}


//
// panel groups
//

.panel-group {
  display: flex;
  flex-direction: column;

  .panel {
    border-radius: 0;
    border: none;
    border-right: $panel-border-width solid $panel-border-color;
    margin-bottom: $panel-group-margin;
  }

  .panel:last-child {
    border-right: none;
  }

  @include media-breakpoint-up(sm) {
    flex-flow: row wrap;

    .panel {
      // Flexbugs #4: https://github.com/philipwalton/flexbugs#4-flex-shorthand-declarations-with-unitless-flex-basis-values-are-ignored
      flex: 1 0 0%;
      margin-bottom: 0;

      + .panel {
        margin-left: 0;
        border-left: 0;
      }


      // Handle rounded corners
      @if $enable-rounded {
        &:first-child {
          @include border-end-radius(0);

          .panel-img-top,
          .panel-header {
            border-top-right-radius: 0;
          }
          .panel-img-bottom,
          .panel-footer {
            border-bottom-right-radius: 0;
          }
        }

        &:last-child {
          @include border-start-radius(0);

          .panel-img-top,
          .panel-header {
            border-top-left-radius: 0;
          }
          .panel-img-bottom,
          .panel-footer {
            border-bottom-left-radius: 0;
          }
        }

        &:only-child {
          @include border-radius($panel-border-radius);

          .panel-img-top,
          .panel-header {
            @include border-top-radius($panel-border-radius);
          }
          .panel-img-bottom,
          .panel-footer {
            @include border-bottom-radius($panel-border-radius);
          }
        }

        &:not(:first-child):not(:last-child):not(:only-child) {
          @include border-radius(0);

          .panel-img-top,
          .panel-img-bottom,
          .panel-header,
          .panel-footer {
            @include border-radius(0);
          }
        }
      }
    }
  }
}


//
// Columns
//

.panel-columns {
  padding: $panel-spacer;
  .panel {
    margin-bottom: $panel-columns-margin;
  }

  @include media-breakpoint-up(sm) {
    column-count: $panel-columns-count;
    column-gap: $panel-columns-gap;

    .panel {
      display: inline-block; // Don't let them vertically span multiple columns
      width: 100%; // Don't let their width change
    }
  }
}