core/misc/dialog/off-canvas/css/titlebar.pcss.css
/**
 * @file
 * Styling for the titlebar within the off-canvas dialog.
 *
 * @internal
 */

#drupal-off-canvas-wrapper {
  --off-canvas-title-padding: calc(3 * var(--off-canvas-vertical-spacing-unit));
  --off-canvas-title-background-color: #2d2d2d;
  --off-canvas-title-text-color: #fff;
  --off-canvas-title-font-size: 16px;

  & .ui-dialog-titlebar {
    position: relative;
    margin: 0 calc(-1 * var(--off-canvas-padding));
    padding: var(--off-canvas-title-padding) 50px;
    color: var(--off-canvas-title-text-color);
    background-color: var(--off-canvas-title-background-color);
    font-family: var(--off-canvas-title-font-family);
    font-size: var(--off-canvas-title-font-size);
    font-weight: bold;

    /* The pencil icon. */
    &::before {
      position: absolute;
      top: 0;
      inset-inline-start: 1em;
      display: block;
      width: 20px;
      height: 100%;
      content: "";
      background-color: currentColor;
      mask-image: url(../../../icons/ffffff/pencil.svg);
      mask-repeat: no-repeat;
      mask-size: contain;
      mask-position: center;

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

  /* Close button. */
  & .ui-dialog-titlebar-close {
    position: absolute;
    top: 50%;
    inset-inline: auto 10px;
    overflow: hidden;
    width: 30px;
    height: 30px;
    cursor: pointer;
    transform: translateY(-50%);
    text-indent: -9999px;
    color: inherit;
    border: 1px solid transparent;
    background-color: transparent;
    appearance: none;

    &:focus {
      outline: solid 2px currentColor;
      outline-offset: 2px;
    }

    /* The plus icon. */
    &::before,
    &::after {
      position: absolute;
      top: calc(50% - 1px);
      left: 50%;
      width: 50%;
      height: 0;
      content: "";
      border-top: solid 2px currentColor;
    }

    &::before {
      transform: translate(-50%, 50%) rotate(-45deg);
    }

    &::after {
      transform: translate(-50%, 50%) rotate(45deg);
    }

    /* Hide the default jQuery UI dialog close button. */
    & .ui-icon {
      display: none;
    }
  }
}
