wagtail/client/scss/components/_panel.scss

$header-icon-size: theme('spacing.4');
$header-button-size: theme('spacing.6');

.w-panel {
  --header-gap: 0;
  margin-bottom: calc(
    theme('spacing.5') + theme('spacing.5') * var(--w-density-factor)
  );

  @include media-breakpoint-up(sm) {
    --header-gap: theme('spacing.4');
  }

  .content-locked &__content {
    cursor: not-allowed;
    user-select: none;

    > * {
      pointer-events: none;
    }
  }
}

.w-panel__header {
  display: flex;
  align-items: center;
  margin-bottom: theme('spacing.[0.5]');
  margin-inline-start: calc(-1 * #{$mobile-nice-padding});

  @include media-breakpoint-up(sm) {
    margin-inline-start: calc(
      -1 * ((2 * $header-button-size) + var(--header-gap))
    );
  }
}

.w-panel__heading {
  @apply w-h3;
  display: inline-block;
  margin: 0;
  margin-inline-start: var(--header-gap);
  padding-inline-end: theme('spacing.2');
  white-space: nowrap;
  text-overflow: ellipsis;
  cursor: pointer;

  label {
    cursor: pointer;
  }

  @include media-breakpoint-up(md) {
    padding-inline-end: theme('spacing.5');
  }
}

.w-panel__heading--label {
  @apply w-label-1;
}

.w-panel__anchor,
.w-panel__toggle,
.w-panel__controls .button.button--icon {
  @include show-focus-outline-inside();
  display: inline-grid;
  justify-content: center;
  align-content: center;
  color: theme('colors.icon-primary');
  border-radius: theme('borderRadius.full');
  margin: 0;
  padding: 0;
  width: $header-button-size;
  height: $header-button-size;

  &:focus-visible,
  &:hover {
    color: theme('colors.icon-primary-hover');
    background-color: theme('colors.white-10');

    @media (forced-colors: active) {
      border: 1px solid currentColor;
    }
  }

  &[disabled] {
    color: theme('colors.text-placeholder');
    cursor: not-allowed;
    // Counter hover styles.
    background-color: transparent;

    @media (forced-colors: active) {
      color: GrayText;
    }
  }
}

.w-panel__anchor {
  // Only hide anchors for devices that support hover interactions.
  @media (hover: hover) {
    .w-panel__header:not(:hover, :focus-within) & {
      opacity: 0;
    }
  }
}

// The suffix anchor is intended for small viewports only.
.w-panel__anchor--suffix {
  @include media-breakpoint-up(sm) {
    display: none;
  }
}

// The prefix anchor can be used when there is enough space in the margin of the page.
.w-panel__anchor--prefix {
  display: none;

  @include media-breakpoint-up(sm) {
    display: inline-grid;
  }
}

.w-panel__toggle {
  appearance: none;
  background: transparent;
}

.w-panel__icon {
  width: $header-icon-size;
  height: $header-icon-size;

  // Only rotate the default caret icon, not custom ones.
  [aria-expanded='false'] &.icon-placeholder {
    transform: rotate(-90deg);
  }

  &.icon-link {
    width: theme('spacing.[3.5]');
    height: theme('spacing.[3.5]');
  }
}

.w-panel__divider {
  flex: 1;
}

.w-panel__controls {
  // Prevent shrinking of the buttons when header text is long.
  flex-shrink: 0;
  // Add additional invisible padding for a more forgiving hover area.
  padding: theme('spacing.4');
  margin: calc(-1 * theme('spacing.4'));
  margin-inline-end: calc(-1 * theme('spacing.8'));
  margin-inline-start: 0;

  @include media-breakpoint-up(sm) {
    margin: calc(-1 * theme('spacing.4'));
    margin-inline-start: 0;
  }
}

.w-panel__wrapper {
  @include max-form-width();
}