/* ==========================================================================
   Header Navigation Bar
   ========================================================================== */
.nav {
  height: 56px;
  background: var(--color-bg);
  border-bottom: 2px solid var(--color-divider);
  padding: 0 var(--space-4);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  z-index: 100;
  flex-shrink: 0;
}

.nav-brand-group {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.nav-logo-badge {
  background: var(--color-accent);
  color: #fff;
  font-weight: 900;
  font-size: 13px;
  letter-spacing: 0.05em;
  padding: 4px 8px;
  text-transform: uppercase;
}

.nav-brand-title {
  font-family: var(--font-heading);
  font-weight: var(--font-heading-weight);
  font-size: 16px;
  letter-spacing: -0.02em;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-version-tag {
  font-size: 10px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-accent-700);
  border: 1px solid var(--color-divider);
  padding: 1px 6px;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* ==========================================================================
   Main Workspace Layout
   ========================================================================== */
.main-workspace {
  flex: 1;
  min-height: 0;
  display: grid;
  grid-template-columns: 420px 1fr;
}

/* Sidebar Panel */
.sidebar {
  background: var(--color-bg);
  border-right: 2px solid var(--color-divider);
  overflow-y: auto;
  padding: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

/* Viewport & Preview Pane Area */
.preview-pane {
  background: var(--viewport-bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-8);
  position: relative;
  overflow: hidden;
  user-select: none;
}

/* Viewport Status & Scale Bar (Bottom Right) */
.viewport-status-bar {
  position: absolute;
  bottom: var(--space-4);
  right: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  box-shadow: var(--shadow-sm);
  padding: 6px 12px;
  display: flex;
  align-items: center;
  gap: var(--space-4);
  font-size: 11px;
  font-weight: 600;
  z-index: 50;
}

.viewport-status-bar label {
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
}

.zoom-group {
  display: flex;
  align-items: center;
  gap: 8px;
}

.zoom-group input[type="range"] {
  width: 80px;
  margin: 0;
}

/* ==========================================================================
   Master Designs Bar (Artboards / Multi-Page Slider)
   ========================================================================== */
.master-designs-bar {
  position: absolute;
  bottom: var(--space-4);
  left: var(--space-4);
  max-width: calc(100% - 370px);
  background: var(--color-surface);
  border: 1px solid var(--color-divider);
  box-shadow: var(--shadow-sm);
  padding: 4px 8px;
  display: flex;
  align-items: center;
  gap: 8px;
  z-index: 50;
  overflow: hidden;
}

.master-designs-label {
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.08em;
  color: color-mix(in srgb, var(--color-text) 60%, transparent);
  white-space: nowrap;
  user-select: none;
}

.master-designs-tabs {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
  overflow-x: auto;
  scrollbar-width: thin;
}

.design-tab {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 8px;
  background: var(--color-bg);
  border: 1px solid var(--color-divider);
  font-family: var(--font-heading);
  font-size: 11px;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
  user-select: none;
  transition: background 0.15s ease, border-color 0.15s ease;
  border-radius: 0 !important;
}

.design-tab:hover {
  border-color: var(--color-text);
}

.design-tab.active {
  background: var(--color-accent);
  color: #fff;
  border-color: var(--color-accent);
}

.master-designs-actions {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-shrink: 0;
}