/* ============================================================
   LAYOUT — App shell, topbar, sidebar, center, right panel
   ============================================================ */

/* ── App shell ── */
#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* ══════════════════════════════════════════
   TOP BAR
   ══════════════════════════════════════════ */
.topbar {
  height: var(--topbar-height);
  background: var(--color-white);
  border-bottom: var(--border-light);
  padding: 0 var(--sp-md);
  display: flex;
  align-items: center;
  gap: var(--sp-md);
  flex-shrink: 0;
  z-index: 100;
  box-shadow: 0 1px 8px rgba(0,48,73,0.06);
}

.topbar__logo {
  display: flex;
  align-items: center;
  gap: var(--sp-xs);
  text-decoration: none;
  overflow: hidden;
}

.topbar__logo-img {
  display: block;
  width: 32px;
  height: 32px;
  max-width: 32px;
  max-height: 32px;
  object-fit: contain;
  flex-shrink: 0;
}

.topbar__logo-mark {
  width: 32px;
  height: 32px;
  background: var(--color-navy);
  border-radius: var(--radius-btn);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  flex-shrink: 0;
}

.topbar__title {
  font-family: var(--font-display);
  font-size: 18px;
  color: var(--color-navy);
  white-space: nowrap;
}

.topbar__tagline {
  font-size: var(--fs-caption);
  font-family: var(--font-secondary);
  color: var(--color-text-caption);
  border-left: var(--border-light);
  padding-left: var(--sp-md);
  display: none;
}

@media (min-width: 900px) {
  .topbar__tagline { display: block; }
}

/* ── Steps indicator ── */
.topbar__steps {
  display: flex;
  align-items: center;
  gap: var(--sp-xs);
  margin-left: auto;
}

.step-pill {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  font-size: var(--fs-caption);
  font-family: var(--font-secondary);
  font-weight: 500;
  border: 1.5px solid rgba(0,48,73,0.14);
  color: var(--color-text-caption);
  background: transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.step-pill .step-num {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: rgba(0,48,73,0.08);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 600;
  flex-shrink: 0;
}

.step-pill.active {
  background: var(--color-navy);
  border-color: var(--color-navy);
  color: white;
}

.step-pill.active .step-num {
  background: rgba(255,255,255,0.25);
}

.step-pill.done {
  border-color: rgba(0,48,73,0.14);
  color: var(--color-text-muted);
}

.step-pill.done .step-num {
  background: rgba(214,40,40,0.12);
  color: var(--color-crimson);
}

.step-divider {
  width: 20px;
  height: 1px;
  background: rgba(0,48,73,0.14);
}

.topbar__actions {
  display: flex;
  gap: var(--sp-xs);
  margin-left: var(--sp-sm);
}

/* ══════════════════════════════════════════
   WORKSPACE
   ══════════════════════════════════════════ */
.workspace {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* ══════════════════════════════════════════
   LEFT SIDEBAR
   ══════════════════════════════════════════ */
.sidebar {
  width: var(--sidebar-width);
  min-width: 220px;
  background: var(--color-white);
  border-right: var(--border-light);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  flex-shrink: 0;
}

.sidebar__section {
  padding: var(--sp-sm) var(--sp-sm) 0;
  border-bottom: var(--border-subtle);
  padding-bottom: var(--sp-sm);
  flex-shrink: 0;
}

.sidebar__scroll {
  flex: 1;
  overflow-y: auto;
  padding: var(--sp-xs);
}

/* ── Sidebar collapse ── */
.sidebar {
  transition: width var(--transition-normal), min-width var(--transition-normal);
}

.sidebar.collapsed {
  width: 0;
  min-width: 0;
  border-right: none;
}

.sidebar__collapse-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  margin-left: auto;
  margin-right: 4px;
  border: none;
  background: transparent;
  cursor: pointer;
  color: var(--color-text-caption);
  font-size: 12px;
  border-radius: 4px;
  flex-shrink: 0;
}
.sidebar__collapse-btn:hover { background: rgba(0,48,73,0.06); }

.sidebar-expand-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  position: fixed;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  z-index: 90;
  width: 20px;
  height: 48px;
  background: var(--color-white);
  border: var(--border-light);
  border-left: none;
  border-radius: 0 6px 6px 0;
  cursor: pointer;
  color: var(--color-text-caption);
  font-size: 11px;
  box-shadow: 2px 0 8px rgba(0,0,0,0.06);
}
.sidebar-expand-btn:hover { background: var(--surface-panel); }

/* ── Sidebar tab nav ── */
.sidebar__tabs {
  display: flex;
  border-bottom: var(--border-light);
  flex-shrink: 0;
}

.sidebar__tab {
  flex: 1;
  padding: 10px 8px;
  font-size: var(--fs-caption);
  font-family: var(--font-secondary);
  font-weight: 500;
  color: var(--color-text-caption);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-align: center;
}

.sidebar__tab:hover { color: var(--color-navy); }

.sidebar__tab.active {
  color: var(--color-crimson);
  border-bottom-color: var(--color-crimson);
}

.sidebar__tab-panel {
  display: none;
  flex-direction: column;
  flex: 1;
  overflow: hidden;
}

.sidebar__tab-panel.active {
  display: flex;
}

/* ══════════════════════════════════════════
   CENTER — Wall area
   ══════════════════════════════════════════ */
.center {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: #e8e4de;
}

.wall-toolbar {
  padding: 8px var(--sp-md);
  background: var(--color-white);
  border-bottom: var(--border-light);
  display: flex;
  align-items: center;
  gap: var(--sp-sm);
  flex-wrap: wrap;
  flex-shrink: 0;
}

.wall-toolbar__group {
  display: flex;
  align-items: center;
  gap: 6px;
}

.wall-toolbar__divider {
  width: 1px;
  height: 20px;
  background: rgba(0,48,73,0.12);
  margin: 0 4px;
}

.wall-viewport {
  flex: 1;
  overflow: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--sp-lg);
  position: relative;
}

/* checkerboard hint for viewport bg */
.wall-viewport::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(45deg, rgba(0,0,0,0.012) 0, rgba(0,0,0,0.012) 1px, transparent 0, transparent 50%);
  background-size: 18px 18px;
  pointer-events: none;
}

/* ══════════════════════════════════════════
   RIGHT PANEL
   ══════════════════════════════════════════ */
.rpanel {
  width: var(--rpanel-width);
  background: var(--color-white);
  border-left: var(--border-light);
  padding: var(--sp-sm);
  overflow-y: auto;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  gap: var(--sp-sm);
  transition: width var(--transition-normal), padding var(--transition-normal);
}

.rpanel.collapsed {
  width: 0;
  padding: 0;
  border-left: none;
  overflow: hidden;
}

/* ── Frame shelf (unused frames from layout) ── */
.frame-shelf {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 16px;
  margin-top: 12px;
  background: var(--color-white);
  border: 1.5px dashed rgba(0,48,73,0.18);
  border-radius: 10px;
  flex-wrap: wrap;
  max-width: 820px;
}

.shelf-thumb {
  width: 52px;
  height: 52px;
  border-radius: 6px;
  overflow: hidden;
  border: 1.5px solid rgba(0,48,73,0.14);
  background: var(--surface-panel);
  cursor: grab;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 600;
  color: var(--color-text-caption);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.shelf-thumb:hover {
  transform: scale(1.08);
  box-shadow: 0 4px 12px rgba(0,0,0,0.14);
}

.shelf-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  pointer-events: none;
}

/* Drop highlight — user is dragging a frame over the shelf */
.frame-shelf.shelf--drop-active {
  border-color: var(--color-crimson);
  background: rgba(214,40,40,0.06);
  box-shadow: 0 0 0 2px rgba(214,40,40,0.2);
}

/* ── Reference photo overlay controls (toolbar) ── */
.ref-overlay-controls {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  background: rgba(0,48,73,0.05);
  border: 1px solid rgba(0,48,73,0.12);
  border-radius: 8px;
}

.ref-overlay-controls__label {
  font-size: 11px;
  font-family: var(--font-secondary);
  color: var(--color-text-caption);
  white-space: nowrap;
  font-weight: 500;
}

.ref-overlay-controls__actions {
  display: flex;
  align-items: center;
  gap: 4px;
}

.ref-overlay-controls__opacity-label {
  display: flex;
  align-items: center;
  color: var(--color-text-caption);
  opacity: 0.7;
}

.ref-overlay-controls__slider {
  width: 56px;
  accent-color: var(--color-navy);
  cursor: pointer;
}

/* ── Reference photo pane (below wall) ── */
.ref-photo-strip {
  background: var(--color-white);
  border-top: var(--border-light);
  flex-shrink: 0;
  max-height: 220px;
  overflow: hidden;
}

.ref-photo-strip__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 12px;
  border-bottom: var(--border-subtle);
}

.ref-photo-strip__body {
  padding: 8px 12px;
  overflow-x: auto;
  display: flex;
  gap: 12px;
  align-items: center;
}

.rpanel__group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.rpanel__group + .rpanel__group {
  padding-top: var(--sp-sm);
  border-top: var(--border-subtle);
}

/* ══════════════════════════════════════════
   STEP PANELS (full-page overlays)
   ══════════════════════════════════════════ */
.step-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,48,73,0.45);
  z-index: 200;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--sp-md);
}

.step-overlay.hidden { display: none; }

.step-modal {
  background: var(--color-white);
  border-radius: var(--radius-modal);
  padding: var(--sp-lg);
  max-width: 680px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 24px 80px rgba(0,48,73,0.22);
}