@layer lu-shell {
  :root {
    --lu-desktop-topbar-height: 3.5rem;
    --lu-desktop-sidebar-width: 15.5rem;
    --lu-desktop-rail-width: 3.5rem;
    --lu-desktop-rail-expanded-width: 14rem;
    --lu-desktop-statusbar-height: 1.75rem;
    --lu-mobile-header-height: 3.25rem;
    --lu-mobile-navbar-height: 3.75rem;
    --lu-embedded-topbar-height: 3.25rem;
    --lu-embedded-statusbar-height: 2rem;
  }

  /* ══════════════════════════════════════════════════════════════════════════
     DESKTOP SHELL
  ══════════════════════════════════════════════════════════════════════════ */

  .lu-desktop-shell {
    display: flex;
    flex-direction: column;
    /* FIX-1: Use 100dvh — let the framework handle viewport height out of the box */
    height: 100dvh;
    width: 100%;
    overflow: hidden;
    background: var(--lu-color-surface-raised, var(--color-zinc-950, #09090b));
    color: var(--lu-color-text, inherit);
  }

  /* Shell content wrapper: rail + sidebar + main content (flex row) */
  .lu-desktop-shell-content-wrapper {
    display: flex;
    flex: 1;
    width: 100%;
    overflow: hidden;
    min-height: 0;
    /* Prevents flex child from overflowing its parent */
  }

  /* Main content area: fills remaining width */
  .lu-desktop-shell-main-content {
    display: flex;
    flex: 1;
    flex-direction: column;
    overflow: hidden;
    position: relative;
    min-width: 0;
  }

  /* ── Desktop TopBar ─────────────────────────────────────────────────────── */
  .lu-desktop-top-bar {
    display: grid;
    /* 3-zone grid: left/center/right — center is always centered regardless of sibling widths */
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    height: var(--lu-desktop-topbar-height);
    flex-shrink: 0;
    width: 100%;
    border-bottom: 1px solid var(--lu-color-border, rgba(255, 255, 255, 0.08));
    background: var(--lu-color-surface-raised, var(--color-zinc-950, #09090b));
    backdrop-filter: blur(8px);
    box-shadow: 0 1px 0 var(--lu-color-border, rgba(255, 255, 255, 0.08)), 0 4px 16px rgba(0, 0, 0, 0.1);
    padding-inline: var(--lu-space-4, 1rem);
    gap: var(--lu-space-3, 0.75rem);
    z-index: 10;
  }

  .lu-desktop-top-bar__left {
    display: flex;
    justify-content: flex-start;
    align-items: center;
    gap: var(--lu-space-2, 0.5rem);
  }

  .lu-desktop-top-bar__center {
    display: flex;
    justify-content: center;
    align-items: center;
  }

  .lu-desktop-top-bar__right {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: var(--lu-space-2, 0.5rem);
  }

  /* ── Desktop Sidebar ────────────────────────────────────────────────────── */
  .lu-desktop-sidebar {
    display: flex;
    flex-direction: column;
    width: var(--lu-desktop-sidebar-width);
    flex-shrink: 0;
    height: 100%;
    border-right: 1px solid var(--lu-color-border, rgba(255, 255, 255, 0.08));
    background: var(--lu-color-surface, var(--color-zinc-900, #18181b));
    transition: width 0.2s ease, opacity 0.2s ease;
    overflow: hidden;
  }

  .lu-desktop-sidebar--collapsed {
    width: 0;
    opacity: 0;
    pointer-events: none;
    border-right: none;
  }

  .lu-desktop-sidebar-header {
    padding: var(--lu-space-3, 0.75rem);
    padding-bottom: var(--lu-space-2, 0.5rem);
    flex-shrink: 0;
    border-bottom: 1px solid var(--lu-color-border, rgba(255, 255, 255, 0.08));
  }

  .lu-desktop-sidebar-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    padding-block: var(--lu-space-1, 0.25rem);
    padding-inline: 0;
    min-height: 0;
  }

  .lu-desktop-sidebar-footer {
    padding: var(--lu-space-2, 0.5rem) var(--lu-space-3, 0.75rem) var(--lu-space-3, 0.75rem);
    flex-shrink: 0;
    border-top: 1px solid var(--lu-color-border, rgba(255, 255, 255, 0.08));
  }

  /* ── Desktop Rail Bar ───────────────────────────────────────────────────── */
  .lu-desktop-rail-bar {
    display: flex;
    flex-direction: column;
    width: var(--lu-desktop-rail-width);
    height: 100%;
    flex-shrink: 0;
    overflow: hidden;
    border-right: 1px solid var(--lu-color-border, rgba(255, 255, 255, 0.08));
    background: var(--lu-color-surface-raised, var(--color-zinc-950, #09090b));
    transition: width 0.2s ease;
    padding-block: var(--lu-space-1, 0.25rem);
  }

  .lu-desktop-rail-bar--expanded {
    width: var(--lu-desktop-rail-expanded-width);
  }

  /* ── Desktop Rail Item ──────────────────────────────────────────────────── */
  .lu-desktop-rail-item {
    display: flex;
    align-items: center;
    gap: var(--lu-space-3, 0.75rem);
    padding: var(--lu-space-2, 0.5rem) var(--lu-space-3, 0.75rem);
    color: var(--lu-color-text-muted, rgba(255, 255, 255, 0.45));
    cursor: pointer;
    white-space: nowrap;
    overflow: hidden;
    transition: background 0.15s ease, color 0.15s ease;
    background: transparent;
    border: none;
    font-family: inherit;
    font-size: var(--lu-text-sm, 0.875rem);
    text-align: left;
    border-radius: var(--lu-radius-sm, 0.375rem);
    margin-inline: var(--lu-space-1, 0.25rem);
    width: calc(100% - 0.5rem);
  }

  .lu-desktop-rail-item:hover {
    background: var(--lu-color-surface-hover, rgba(255, 255, 255, 0.06));
    color: var(--lu-color-text, rgba(255, 255, 255, 0.9));
  }

  .lu-desktop-rail-item--active {
    background: color-mix(in srgb, var(--lu-color-primary, #6366f1) 12%, transparent);
    color: var(--lu-color-primary, #6366f1);
    font-weight: 500;
  }

  .lu-desktop-rail-item-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 1.25rem;
    height: 1.25rem;
    flex-shrink: 0;
  }

  .lu-desktop-rail-item-label {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: var(--lu-text-sm, 0.875rem);
  }

  /* ── Desktop Status Bar ─────────────────────────────────────────────────── */
  .lu-desktop-status-bar {
    --lu-icon-size: 1rem;
    display: grid;
    /* FIX-4: Proper 3-zone grid for status bar zones */
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    height: var(--lu-desktop-statusbar-height);
    flex-shrink: 0;
    width: 100%;
    border-top: 1px solid var(--lu-color-border, rgba(255, 255, 255, 0.08));
    background: var(--lu-color-surface, var(--color-zinc-900, #18181b));
    padding-inline: var(--lu-space-4, 1rem);
    font-size: 0.6875rem;
    color: var(--lu-color-text-muted, rgba(255, 255, 255, 0.45));
    z-index: 10;
  }

  /* FIX-4: StatusBar zone classes */
  .lu-desktop-status-bar__left {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: var(--lu-space-2, 0.5rem);
  }

  .lu-desktop-status-bar__center {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--lu-space-2, 0.5rem);
  }

  .lu-desktop-status-bar__right {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: var(--lu-space-2, 0.5rem);
  }

  /* ══════════════════════════════════════════════════════════════════════════
     MOBILE SHELL
  ══════════════════════════════════════════════════════════════════════════ */

  .lu-mobile-shell {
    display: flex;
    flex-direction: column;
    /* FIX-1: Use 100dvh — let framework handle height */
    height: 100dvh;
    width: 100%;
    overflow: hidden;
    background: var(--lu-color-surface, var(--color-zinc-900, #18181b));
    color: var(--lu-color-text, inherit);
  }

  /* FIX-6: Content area is the only flex: 1 element; navbar gets flex-shrink: 0 via its wrapper */
  .lu-mobile-shell-content {
    flex: 1;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    min-height: 0;
  }

  /* FIX-6: Navbar wrapper — ensure it never gets squashed */
  .lu-mobile-shell-navbar {
    flex-shrink: 0;
  }

  /* ── Mobile Header ──────────────────────────────────────────────────────── */
  .lu-mobile-header {
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    height: var(--lu-mobile-header-height);
    flex-shrink: 0;
    padding-inline: var(--lu-space-4, 1rem);
    border-bottom: 1px solid var(--lu-color-border, rgba(255, 255, 255, 0.08));
    background: color-mix(in srgb, var(--lu-color-surface-raised, #09090b) 85%, transparent);
    backdrop-filter: blur(12px);
    z-index: 10;
  }

  .lu-mobile-header__left {
    display: flex;
    justify-content: flex-start;
    align-items: center;
    gap: var(--lu-space-2, 0.5rem);
  }

  .lu-mobile-header__center {
    display: flex;
    justify-content: center;
    align-items: center;
  }

  .lu-mobile-header__right {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: var(--lu-space-2, 0.5rem);
  }

  /* ── Mobile NavBar ──────────────────────────────────────────────────────── */
  .lu-mobile-nav-bar {
    display: flex;
    align-items: stretch;
    justify-content: space-around;
    height: var(--lu-mobile-navbar-height);
    border-top: 1px solid var(--lu-color-border, rgba(255, 255, 255, 0.08));
    background: color-mix(in srgb, var(--lu-color-surface-raised, #09090b) 85%, transparent);
    backdrop-filter: blur(12px);
    position: relative;
    z-index: 10;
  }

  .lu-mobile-nav-bar-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 3px;
    flex: 1;
    min-height: 44px;
    /* WCAG touch target */
    background: transparent;
    border: none;
    font-family: inherit;
    color: var(--lu-color-text-muted, rgba(255, 255, 255, 0.45));
    cursor: pointer;
    transition: color 0.15s ease;
    padding-block: var(--lu-space-1, 0.25rem);
  }

  .lu-mobile-nav-bar-item:hover {
    color: var(--lu-color-text, rgba(255, 255, 255, 0.9));
  }

  .lu-mobile-nav-bar-item--active {
    color: var(--lu-color-primary, #6366f1);
    position: relative;
  }

  .lu-mobile-nav-bar-item--active::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 24px;
    height: 3px;
    border-radius: 0 0 3px 3px;
    background-color: var(--lu-color-primary, #6366f1);
  }

  .lu-mobile-nav-bar-item[disabled],
  .lu-mobile-nav-bar-item:disabled {
    opacity: 0.4;
    pointer-events: none;
  }

  .lu-mobile-nav-bar-item__icon {
    --lu-icon-size: 1.25rem;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 1.5rem;
    height: 1.5rem;
  }

  .lu-mobile-nav-bar-item__label {
    font-size: var(--lu-text-xs, 0.75rem);
    line-height: 1;
    white-space: nowrap;
  }

  /* ══════════════════════════════════════════════════════════════════════════
     EMBEDDED SHELL
  ══════════════════════════════════════════════════════════════════════════ */

  .lu-embedded-shell {
    display: flex;
    flex-direction: column;
    /* FIX-1: Use 100dvh */
    height: 100dvh;
    width: 100%;
    overflow: hidden;
    touch-action: none;
    user-select: none;
    background: var(--lu-color-surface, var(--color-zinc-900, #18181b));
    color: var(--lu-color-text, inherit);
  }

  .lu-embedded-shell-content {
    flex: 1;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    min-height: 0;
  }

  /* ── Embedded TopBar ────────────────────────────────────────────────────── */
  .lu-embedded-top-bar {
    /* FIX-5: Grid layout for true 3-zone centering */
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    height: var(--lu-embedded-topbar-height);
    flex-shrink: 0;
    border-bottom: 1px solid color-mix(in srgb, var(--lu-color-primary, #6366f1) 30%, var(--lu-color-border, rgba(255, 255, 255, 0.08)));
    background: var(--lu-color-surface-raised, var(--color-zinc-950, #09090b));
    box-shadow: 0 1px 0 var(--lu-color-border, rgba(255, 255, 255, 0.08)), 0 4px 16px rgba(0, 0, 0, 0.1);
    padding-inline: var(--lu-space-4, 1rem);
    gap: var(--lu-space-3, 0.75rem);
    z-index: 10;
  }

  .lu-embedded-top-bar__left {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: var(--lu-space-2, 0.5rem);
  }

  .lu-embedded-top-bar__center {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--lu-space-2, 0.5rem);
  }

  .lu-embedded-top-bar__right {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: var(--lu-space-2, 0.5rem);
  }

  /* ── Embedded StatusBar ─────────────────────────────────────────────────── */
  .lu-embedded-status-bar {
    --lu-icon-size: 1rem;
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    height: var(--lu-embedded-statusbar-height);
    flex-shrink: 0;
    border-top: 1px solid color-mix(in srgb, var(--lu-color-primary, #6366f1) 20%, var(--lu-color-border, rgba(255, 255, 255, 0.08)));
    background: var(--lu-color-surface, var(--color-zinc-900, #18181b));
    padding-inline: var(--lu-space-4, 1rem);
    font-size: 0.6875rem;
    color: var(--lu-color-text-muted, rgba(255, 255, 255, 0.45));
    z-index: 10;
  }

  .lu-embedded-status-bar__left {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: var(--lu-space-2, 0.5rem);
  }

  .lu-embedded-status-bar__center {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--lu-space-2, 0.5rem);
  }

  .lu-embedded-status-bar__right {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: var(--lu-space-2, 0.5rem);
  }

  /* ══════════════════════════════════════════════════════════════════════════
     SHOWCASE EMBEDDED INPUT RECIPE
  ══════════════════════════════════════════════════════════════════════════ */

  .lu-embedded-barcode-input {
    display: flex;
    flex-direction: column;
    width: 100%;
  }

  .lu-embedded-barcode-input-field {
    display: flex;
    align-items: center;
    gap: var(--lu-space-2, 0.5rem);
    width: 100%;
    padding: var(--lu-space-2, 0.5rem) var(--lu-space-3, 0.75rem);
    background: var(--lu-color-surface, var(--color-zinc-900, #18181b));
    border: 1.5px solid var(--lu-color-border, rgba(255, 255, 255, 0.08));
    border-radius: var(--lu-radius-input, 0.5rem);
    transition: border-color 0.15s ease;
  }

  .lu-embedded-barcode-input-field--scanning {
    border-color: var(--lu-color-primary, #6366f1);
    box-shadow: 0 0 0 3px color-mix(in srgb, var(--lu-color-primary, #6366f1) 20%, transparent);
  }

  .lu-embedded-barcode-input-inner {
    flex: 1;
    border: none;
    background: transparent;
    outline: none;
    font-size: var(--lu-text-sm, 0.875rem);
    color: var(--lu-color-text, rgba(255, 255, 255, 0.9));
  }

  .lu-embedded-barcode-input-inner::placeholder {
    color: var(--lu-color-text-disabled, rgba(255, 255, 255, 0.25));
  }

  /* ══════════════════════════════════════════════════════════════════════════
     VARIANTS
  ══════════════════════════════════════════════════════════════════════════ */

  /* Desktop shell variants */
  .lu-desktop-shell--compact .lu-desktop-top-bar {
    height: 2.75rem;
  }

  .lu-desktop-top-bar--bordered {
    border-bottom-width: 2px;
  }

  .lu-desktop-top-bar--transparent {
    background: transparent;
    backdrop-filter: none;
    border-bottom-color: transparent;
  }

  .lu-desktop-top-bar--compact {
    height: 2.75rem;
  }

  /* Desktop sidebar variants */
  .lu-desktop-sidebar--narrow {
    width: 11rem;
  }

  .lu-desktop-sidebar--bordered {
    border-right-width: 2px;
  }

  /* Mobile variants */
  .lu-mobile-shell--full {
    height: 100dvh;
  }

  .lu-mobile-header--transparent {
    background: transparent;
    border-bottom-color: transparent;
  }

  /* Embedded variants */
  .lu-embedded-shell--fullscreen {
    height: 100dvh;
  }

  .lu-embedded-top-bar--compact {
    height: 2.25rem;
  }

  .lu-embedded-status-bar--icon-row {
    height: 3rem;
  }
}