/* ============================================================================
   Astu Layout — Sidebar, Topbar, Content
   Dark-first design system per DESIGN.md
   ============================================================================ */

/* ====== APP SHELL ====== */

.app-container {
  min-height: 100vh;
  background: var(--bg-void);
}

/* ====== SIDEBAR ====== */

.sidebar {
  width: var(--sidebar-width);
  background: var(--bg-surface);
  border-right: 1px solid var(--border-subtle);
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: var(--z-sidebar);
  overflow-y: auto;
  overflow-x: hidden;
  transition: width var(--transition-slow);
  display: flex;
  flex-direction: column;
}

.sidebar-header {
  padding: var(--space-xl) var(--space-xl) var(--space-lg);
}

.sidebar-logo {
  font-family: var(--font-heading);
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  display: block;
  letter-spacing: -0.5px;
}
.sidebar-logo:hover {
  color: var(--text-primary);
  text-decoration: none;
}

.sidebar-flag {
  height: 3px;
  background: var(--flag-stripe);
  margin: var(--space-md) 0 var(--space-lg);
  border-radius: 2px;
}

.sidebar-nav {
  flex: 1;
  padding: 0 var(--space-md);
}

.nav-section {
  margin-bottom: var(--space-xl);
}

.nav-section-title {
  font-size: 11px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-tertiary);
  padding: var(--space-sm) var(--space-md);
  margin-bottom: var(--space-xs);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 400;
  text-decoration: none;
  transition: all var(--transition-fast);
  margin-bottom: 1px;
}

.nav-item:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
  text-decoration: none;
}

.nav-item.active {
  background: var(--color-primary-ghost);
  color: var(--color-primary);
  font-weight: 500;
}

.nav-item .icon,
.nav-item i {
  width: 18px;
  font-size: 16px;
  text-align: center;
  flex-shrink: 0;
  opacity: 0.7;
}
.nav-item.active .icon,
.nav-item.active i {
  opacity: 1;
}

.nav-submenu {
  padding-left: var(--space-lg);
}

.nav-submenu .nav-item {
  font-size: 13px;
  padding: 6px var(--space-md);
}

/* Sidebar footer */
.sidebar-footer {
  padding: var(--space-lg);
  border-top: 1px solid var(--border-subtle);
}

/* ====== TOPBAR ====== */

.topbar {
  height: var(--topbar-height);
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--content-padding);
  margin-left: var(--sidebar-width);
  position: sticky;
  top: 0;
  z-index: var(--z-topbar);
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.topbar-search {
  flex: 0 0 320px;
}

.topbar-search .search-input {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  background: var(--bg-card);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  padding: var(--space-sm) var(--space-lg);
}

.topbar-search .search-icon {
  color: var(--text-tertiary);
  font-size: 14px;
  flex-shrink: 0;
}

.topbar-search input {
  background: none;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 13px;
  width: 100%;
}
.topbar-search input::placeholder {
  color: var(--text-tertiary);
}

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

.topbar-btn {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 18px;
  padding: var(--space-sm);
  border-radius: var(--radius-md);
  cursor: pointer;
  position: relative;
  transition: color var(--transition-fast), background var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 36px;
  min-height: 36px;
}
.topbar-btn:hover {
  color: var(--text-primary);
  background: var(--bg-card);
}

.topbar-btn .notification-dot {
  position: absolute;
  top: 6px;
  right: 6px;
  width: 7px;
  height: 7px;
  background: var(--status-urgent);
  border-radius: 50%;
  border: 2px solid var(--bg-surface);
}

.topbar-user {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-secondary);
  font-size: 13px;
  font-family: var(--font-body);
}

.topbar-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 600;
  flex-shrink: 0;
}

/* ====== MAIN CONTENT ====== */

.main-content {
  margin-left: var(--sidebar-width);
  flex: 1;
  min-height: 100vh;
  background: var(--bg-void);
}

.content-wrapper {
  max-width: var(--content-max);
  padding: var(--content-padding);
}

/* ====== PAGE HEADER ====== */

.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-2xl);
  flex-wrap: wrap;
  gap: var(--space-lg);
}

.page-title {
  font-family: var(--font-heading);
  font-size: 20px;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
  letter-spacing: -0.3px;
  line-height: 1.3;
}

.page-subtitle {
  font-family: var(--font-body);
  font-size: 13px;
  color: var(--text-secondary);
  margin: var(--space-xs) 0 0;
}

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

/* ====== BREADCRUMBS ====== */

.breadcrumb-nav {
  margin-bottom: var(--space-lg);
  font-family: var(--font-body);
  font-size: 13px;
  color: var(--text-tertiary);
}
.breadcrumb-nav a {
  color: var(--text-tertiary);
  text-decoration: none;
  transition: color var(--transition-fast);
}
.breadcrumb-nav a:hover {
  color: var(--text-primary);
}
.breadcrumb-nav .sep {
  margin: 0 var(--space-sm);
  opacity: 0.5;
}
.breadcrumb-nav .current {
  color: var(--text-secondary);
}

/* Legacy breadcrumb class support */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
  font-size: 13px;
  color: var(--text-tertiary);
  font-family: var(--font-body);
}
.breadcrumb a {
  color: var(--text-tertiary);
  text-decoration: none;
  transition: color var(--transition-fast);
}
.breadcrumb a:hover {
  color: var(--text-primary);
}
.breadcrumb .separator {
  opacity: 0.5;
}
.breadcrumb .current {
  color: var(--text-secondary);
  font-weight: 500;
}

/* ====== SECTION UTILITIES ====== */

.container {
  max-width: var(--content-max);
  margin: 0 auto;
}

.section {
  margin-bottom: var(--space-3xl);
}

.section-title {
  font-family: var(--font-heading);
  font-size: 16px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-lg);
  line-height: 1.4;
}

.section-label {
  font-size: 11px;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-tertiary);
  margin-bottom: var(--space-md);
}

/* ====== MOBILE ====== */

.sidebar-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 24px;
  padding: var(--space-sm);
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: background var(--transition-fast);
  min-width: 44px;
  min-height: 44px;
  align-items: center;
  justify-content: center;
}
.sidebar-toggle:hover {
  background: var(--bg-card);
}

.sidebar-toggle-icon {
  display: block;
  width: 20px;
  height: 2px;
  background: currentColor;
  box-shadow: 0 -6px 0 currentColor, 0 6px 0 currentColor;
}

.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  z-index: calc(var(--z-sidebar) - 1);
  opacity: 0;
  transition: opacity var(--transition-slow);
}

/* Tablet: sidebar becomes a drawer */
@media (max-width: 1024px) {
  .sidebar {
    transform: translateX(-100%);
    width: 280px;
    transition: transform var(--transition-slow);
  }
  .sidebar.open {
    transform: translateX(0);
  }

  .sidebar-toggle {
    display: flex;
  }

  .sidebar-overlay.active {
    display: block;
    opacity: 1;
  }

  .main-content,
  .topbar {
    margin-left: 0;
  }

  .topbar-search {
    flex: 0 0 200px;
  }

  /* Body scroll lock when sidebar open */
  body.sidebar-open {
    overflow: hidden;
  }
  body.sidebar-open .sidebar-overlay {
    display: block;
    pointer-events: auto;
    opacity: 1;
  }
}

/* Phone: hide search, stack header */
@media (max-width: 768px) {
  .topbar-search {
    display: none;
  }

  .page-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .content-wrapper {
    padding: var(--space-lg);
  }

  .topbar {
    padding: 0 var(--space-lg);
  }
}