adius: var(--panel-border-radius);
    border: 1px solid var(--panel-border-color);
    width: var(--panel-width);
    box-shadow: var(--panel-shadow);
    margin: var(--panel-shadow-margin);

    min-width: 0;
    min-height: 0;

    /* Makes popup constraints work. Round up to avoid subpixel rounding
     * causing overflow, see bug 1846050 */
    max-height: round(up, 100% - 2 * var(--panel-shadow-margin), 1px);
    max-width: round(up, 100% - 2 * var(--panel-shadow-margin), 1px);

    overflow: clip; /* Don't let panel content overflow the border */
  }

  &[orient="vertical"]::part(content) {
    flex-direction: column;
  }
}

/* ::::: arrow panel ::::: */

panel:where([type="arrow"]) {
  appearance: none;
  background-color: transparent;

  &.panel-no-padding::part(content) {
    padding: 0;
  }
}

/* ::::: panel animations ::::: */

.animatable-menupopup,
panel[type="arrow"] {
  transition-timing-function: var(--animation-easing-function), ease-out;

  &:not([animate="false"]) {
    transition-duration: 0.18s;
  }

  @media not (-moz-platform: macos) {
    transition-property: transform, opacity;
    will-change: transform, opacity;
    opacity: 0;
    @media not (prefers-reduced-motion) {
      transform: translateY(-70px);

      &:where([side="bottom"]) {
        transform: translateY(70px);
      }
      /* On some platforms we can't animate the panel position easily, see
       * bug 1385079, bug 1800368, bug 1800442 */
      @media not (-moz-panel-animations) {
        transform: none;
      }
    }
  }

  /* On Mac, use the properties "-moz-window-transform" and "-moz-window-opacity"
   * instead of "transform" and "opacity" for these animations.
   * The -moz-window* properties apply to the whole window including the
   * window's shadow, and they don't affect the window's "shape", so the
   * system doesn't have to recompute the shadow shape during the animation.
   * This makes them a lot faster. These properties are not implemented on
   * other platforms.
   */
  @media (-moz-platform: macos) {
    transition-property:
      -moz-window-transform,
      -moz-window-opacity;
    @media not (prefers-reduced-motion) {
      -moz-window-transform: translateY(-70px);

      &:where([side="bottom"]) {
        -moz-window-transform: translateY(70px);
      }
    }
    /* Only do the fade-in animation on pre-Big Sur to avoid missing shadows on
     * Big Sur+, see bug 1672091. */
    @media not (-moz-mac-big-sur-theme) {
      -moz-window-opacity: 0;
    }
    /* If the @media rule above is removed, then we can also remove this */
    &[animate="cancel"] {
      -moz-window-opacity: 0;
    }
  }

  &[animate="cancel"] {
    -moz-window-transform: none;
    transform: none;
  }

  &:is([animate="false"], [animate="open"]) {
    opacity: 1;
    transform: none;
    -moz-window-opacity: 1;
    -moz-window-transform: none;
    transition-timing-function: var(--animation-easing-function), ease-in-out;
  }

  &[animating] {
    pointer-events: none;
  }
}
PK