/* =================================================================
   Admin Split Grid Layout
   64px Header + 260px LNB + Content Area
   Based on 5-1 Section 3 Design Specification
   ================================================================= */

/* -----------------------------------------------------------------
   1. GRID CONTAINER
   ----------------------------------------------------------------- */
.admin-layout {
  display: grid;
  grid-template-rows: var(--header-h) 1fr;
  grid-template-columns: var(--lnb-w) 1fr;
  grid-template-areas:
    "header header"
    "lnb    content";
  height: 100vh;
  overflow: hidden;
  background: var(--color-bg);
}

/* -----------------------------------------------------------------
   2. HEADER
   ----------------------------------------------------------------- */
.admin-header {
  grid-area: header;
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: 0 var(--space-6);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  z-index: var(--z-sticky);
  height: var(--header-h);
}

/* Logo */
.admin-header__logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  width: calc(var(--lnb-w) - var(--space-6) * 2);
  min-width: 160px;
  flex-shrink: 0;
  text-decoration: none;
  color: var(--color-text);
}
.admin-header__logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--color-primary-500), var(--color-accent-500));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: var(--font-bold);
  font-size: var(--text-lg);
  font-family: var(--font-display);
}
.admin-header__logo-text {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  background: linear-gradient(135deg, var(--color-primary-600), var(--color-accent-600));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Search */
.admin-header__search {
  flex: 1;
  max-width: 480px;
  position: relative;
}
.admin-header__search-input {
  width: 100%;
  height: 40px;
  padding: 0 var(--space-4) 0 var(--space-10);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  background: var(--color-bg-alt);
  font-size: var(--text-sm);
  transition: all var(--duration-fast) var(--ease-default);
  color: var(--color-text);
}
.admin-header__search-input::placeholder {
  color: var(--color-text-muted);
}
.admin-header__search-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
  background: var(--color-surface);
}
.admin-header__search-icon {
  position: absolute;
  left: var(--space-3);
  top: 50%;
  transform: translateY(-50%);
  width: 18px;
  height: 18px;
  color: var(--color-text-muted);
  pointer-events: none;
}

/* Header Actions */
.admin-header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-left: auto;
}

/* Theme Switcher Button */
.theme-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: all var(--duration-normal) var(--ease-spring);
  color: var(--color-text-secondary);
  backdrop-filter: blur(8px);
  flex-shrink: 0;
}
.theme-btn:hover {
  transform: translateY(-2px);
  border-color: var(--color-primary);
  box-shadow: var(--shadow-md);
  color: var(--color-text);
}
.theme-btn svg {
  transition: transform var(--duration-normal) var(--ease-spring);
}
.theme-btn:hover svg {
  transform: rotate(15deg);
}
.moon-icon {
  display: none;
  color: #a78bfa;
}
.sun-icon {
  display: block;
  color: #f59e0b;
}
html[data-theme="dark"] .moon-icon {
  display: block;
}
html[data-theme="dark"] .sun-icon {
  display: none;
}

/* User Profile Dropdown */
.admin-header__profile {
  position: relative;
}
.admin-header__profile-btn {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1_5) var(--space-3);
  border-radius: var(--radius-lg);
  transition: background var(--duration-fast) var(--ease-default);
  cursor: pointer;
}
.admin-header__profile-btn:hover {
  background: var(--color-bg-alt);
}
.admin-header__profile-avatar {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--color-primary-400), var(--color-accent-400));
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: var(--font-semibold);
  font-size: var(--text-sm);
}
.admin-header__profile-name {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text);
}
.admin-header__profile-role {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
}
.admin-header__profile-arrow {
  width: 16px;
  height: 16px;
  color: var(--color-text-muted);
  transition: transform var(--duration-fast) var(--ease-default);
}
.admin-header__profile-btn[aria-expanded="true"] .admin-header__profile-arrow {
  transform: rotate(180deg);
}

/* Profile Dropdown Menu */
.admin-header__profile-menu {
  position: absolute;
  top: calc(100% + var(--space-2));
  right: 0;
  min-width: 200px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--space-1);
  z-index: var(--z-dropdown);
  opacity: 0;
  transform: translateY(-8px);
  pointer-events: none;
  transition: all var(--duration-fast) var(--ease-default);
}
.admin-header__profile-menu.is-open {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}
.admin-header__profile-menu-item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  transition: all var(--duration-fast) var(--ease-default);
}
.admin-header__profile-menu-item:hover {
  background: var(--color-bg-alt);
  color: var(--color-text);
}
.admin-header__profile-menu-item--danger:hover {
  background: var(--color-danger-bg);
  color: var(--color-danger);
}
.admin-header__profile-menu-divider {
  height: 1px;
  background: var(--color-border);
  margin: var(--space-1) 0;
}

/* Mobile hamburger */
.admin-header__hamburger {
  display: flex;
  width: 40px;
  height: 40px;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--color-text);
  flex-shrink: 0;
}
.admin-header__hamburger svg {
  width: 22px;
  height: 22px;
}

/* -----------------------------------------------------------------
   3. LEFT NAVIGATION BAR (LNB)
   ----------------------------------------------------------------- */
.admin-lnb {
  grid-area: lnb;
  background: var(--color-surface);
  border-right: 1px solid var(--color-border);
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--space-4) 0;
  transition: width var(--duration-normal) var(--ease-default);
  scrollbar-width: thin;
  scrollbar-color: var(--color-neutral-300) transparent;
}
.admin-lnb::-webkit-scrollbar { width: 4px; }
.admin-lnb::-webkit-scrollbar-track { background: transparent; }
.admin-lnb::-webkit-scrollbar-thumb {
  background: var(--color-neutral-300);
  border-radius: var(--radius-full);
}

/* LNB Section Label */
.lnb-section-label {
  padding: var(--space-3) var(--space-5) var(--space-2);
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* LNB Menu Item — Level 1 */
.lnb-item {
  position: relative;
}
.lnb-item__trigger {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  width: 100%;
  padding: var(--space-2_5, 10px) var(--space-5);
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-text-secondary);
  border: none;
  background: none;
  cursor: pointer;
  transition: all var(--duration-fast) var(--ease-default);
  text-align: left;
  border-left: 3px solid transparent;
  padding-left: calc(var(--space-5) - 3px);
}
/* --space-2_5 fallback */
.lnb-item__trigger {
  padding-top: 10px;
  padding-bottom: 10px;
}
.lnb-item__trigger:hover {
  background: var(--color-bg-alt);
  color: var(--color-text);
}
.lnb-item__trigger.is-active {
  background: var(--color-primary-50);
  color: var(--color-primary-600);
  border-left-color: var(--color-primary-500);
  font-weight: var(--font-semibold);
}
html[data-theme="dark"] .lnb-item__trigger.is-active {
  background: rgba(59, 130, 246, 0.1);
  color: var(--color-primary-400);
}

.lnb-item__icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  color: currentColor;
  opacity: 0.7;
}
.lnb-item__trigger.is-active .lnb-item__icon {
  opacity: 1;
}

.lnb-item__text {
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.lnb-item__arrow {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  color: var(--color-text-muted);
  transition: transform var(--duration-fast) var(--ease-default);
}
.lnb-item__trigger[aria-expanded="true"] .lnb-item__arrow {
  transform: rotate(180deg);
}

/* LNB Sub Menu — Level 2 (Accordion) */
.lnb-sub {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--duration-normal) var(--ease-default);
  overflow: hidden;
}
.lnb-sub.is-open {
  grid-template-rows: 1fr;
}
.lnb-sub__inner {
  min-height: 0;
}

.lnb-sub__item {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-5) var(--space-2) var(--space-12);
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: all var(--duration-fast) var(--ease-default);
  position: relative;
}
.lnb-sub__item::before {
  content: '';
  width: 4px;
  height: 4px;
  border-radius: var(--radius-full);
  background: var(--color-neutral-300);
  flex-shrink: 0;
  transition: all var(--duration-fast) var(--ease-default);
}
.lnb-sub__item:hover {
  color: var(--color-text);
  background: var(--color-bg-alt);
}
.lnb-sub__item:hover::before {
  background: var(--color-text-secondary);
}
.lnb-sub__item.is-active {
  color: var(--color-primary);
  font-weight: var(--font-medium);
}
.lnb-sub__item.is-active::before {
  background: var(--color-primary);
  width: 6px;
  height: 6px;
}

/* LNB Sub-Sub Menu — Level 3 */
.lnb-sub3 {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--duration-normal) var(--ease-default);
  overflow: hidden;
}
.lnb-sub3.is-open {
  grid-template-rows: 1fr;
}
.lnb-sub3__inner {
  min-height: 0;
}
.lnb-sub3__item {
  display: block;
  padding: var(--space-1_5) var(--space-5) var(--space-1_5) calc(var(--space-12) + var(--space-6));
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  text-decoration: none;
  transition: all var(--duration-fast) var(--ease-default);
}
.lnb-sub3__item:hover {
  color: var(--color-text);
  background: var(--color-bg-alt);
}
.lnb-sub3__item.is-active {
  color: var(--color-primary);
  font-weight: var(--font-medium);
}

/* -----------------------------------------------------------------
   4. CONTENT AREA
   ----------------------------------------------------------------- */
.admin-content {
  grid-area: content;
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--space-6) var(--space-8);
  background: var(--color-bg-alt);
}

/* Page Header with Breadcrumb */
.admin-page-header {
  margin-bottom: var(--space-6);
}
.admin-page-title {
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--color-text);
  margin-top: var(--space-2);
}
.admin-page-desc {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-1);
}
.admin-page-heading-inline {
  display: flex;
  align-items: baseline;
  flex-wrap: nowrap;
  gap: var(--space-2);
  margin-top: var(--space-2);
  width: 100%;
  max-width: 100%;
  min-width: 0;
}
.admin-page-heading-inline .admin-page-title,
.admin-page-heading-inline .admin-page-desc {
  margin-top: 0;
  white-space: nowrap;
}
.admin-page-heading-inline .admin-page-title {
  flex: 0 0 auto;
}
.admin-page-heading-inline .admin-page-desc {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
}
.admin-page-heading-separator {
  flex: 0 0 auto;
  color: var(--color-text-muted);
  font-size: var(--text-sm);
}

/* -----------------------------------------------------------------
   5. RESPONSIVE — Tablet (768~1023px)
   ----------------------------------------------------------------- */
@media (max-width: 1023px) {
  .admin-layout {
    grid-template-columns: var(--lnb-w-mini) 1fr;
  }
  .admin-header__logo-text { display: none; }
  .admin-header__logo {
    width: auto;
    min-width: auto;
  }

  /* LNB: Icon-only collapsed */
  .admin-lnb {
    width: var(--lnb-w-mini);
  }
  .lnb-section-label,
  .lnb-item__text,
  .lnb-item__arrow,
  .lnb-sub { display: none; }

  .lnb-item__trigger {
    justify-content: center;
    padding: var(--space-3);
    border-left: none;
  }
  .lnb-item__icon {
    width: 22px;
    height: 22px;
  }

  /* Hover expand LNB */
  .admin-lnb:hover {
    width: var(--lnb-w);
    position: absolute;
    top: var(--header-h);
    left: 0;
    bottom: 0;
    z-index: var(--z-overlay);
    box-shadow: var(--shadow-xl);
  }
  .admin-lnb:hover .lnb-section-label,
  .admin-lnb:hover .lnb-item__text,
  .admin-lnb:hover .lnb-item__arrow,
  .admin-lnb:hover .lnb-sub { display: initial; }
  .admin-lnb:hover .lnb-sub { display: grid; }
  .admin-lnb:hover .lnb-item__trigger {
    justify-content: flex-start;
    padding: 10px var(--space-5);
    border-left: 3px solid transparent;
    padding-left: calc(var(--space-5) - 3px);
  }

  .admin-content {
    padding: var(--space-4) var(--space-5);
  }
}

/* -----------------------------------------------------------------
   6. RESPONSIVE — Mobile (~767px)
   ----------------------------------------------------------------- */
@media (max-width: 767px) {
  .admin-layout {
    grid-template-columns: 1fr;
    grid-template-areas:
      "header"
      "content";
  }

  .admin-header__hamburger { display: flex; }
  .admin-header__search { display: none; }
  .admin-header__profile-name,
  .admin-header__profile-role { display: none; }

  /* LNB: Hidden by default, slide up modal */
  .admin-lnb {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    top: auto;
    height: 70vh;
    width: 100%;
    z-index: var(--z-modal);
    border-right: none;
    border-top: 1px solid var(--color-border);
    border-radius: var(--radius-xl) var(--radius-xl) 0 0;
    box-shadow: var(--shadow-xl);
    transform: translateY(100%);
    transition: transform var(--duration-normal) var(--ease-default);
  }
  .admin-lnb.is-mobile-open {
    display: block;
    transform: translateY(0);
  }

  /* LNB items re-enable */
  .admin-lnb.is-mobile-open .lnb-section-label,
  .admin-lnb.is-mobile-open .lnb-item__text,
  .admin-lnb.is-mobile-open .lnb-item__arrow { display: initial; }
  .admin-lnb.is-mobile-open .lnb-sub { display: grid; }
  .admin-lnb.is-mobile-open .lnb-item__trigger {
    justify-content: flex-start;
    padding: 10px var(--space-5);
    border-left: 3px solid transparent;
    padding-left: calc(var(--space-5) - 3px);
  }

  /* Mobile overlay backdrop */
  .admin-lnb-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: var(--color-overlay);
    z-index: calc(var(--z-modal) - 1);
  }
  .admin-lnb-overlay.is-visible {
    display: block;
  }

  .admin-content {
    padding: var(--space-4);
  }
}

/* -----------------------------------------------------------------
   7. DESKTOP SIDEBAR COLLAPSE (html.is-lnb-collapsed)
   ----------------------------------------------------------------- */
@media (min-width: 768px) {
  html.is-lnb-collapsed .admin-layout {
    grid-template-columns: var(--lnb-w-mini) 1fr;
  }
  html.is-lnb-collapsed .admin-lnb {
    width: var(--lnb-w-mini);
  }
  html.is-lnb-collapsed .lnb-section-label,
  html.is-lnb-collapsed .lnb-item__text,
  html.is-lnb-collapsed .lnb-item__arrow,
  html.is-lnb-collapsed .lnb-sub {
    display: none;
  }
  html.is-lnb-collapsed .lnb-item__trigger {
    justify-content: center;
    padding: var(--space-3);
    border-left: none;
  }
  html.is-lnb-collapsed .lnb-item__icon {
    width: 22px;
    height: 22px;
  }

  /* Hover Expand Interaction */
  html.is-lnb-collapsed .admin-lnb:hover {
    width: var(--lnb-w);
    position: absolute;
    top: var(--header-h);
    left: 0;
    bottom: 0;
    z-index: var(--z-overlay);
    box-shadow: var(--shadow-xl);
    border-right: 1px solid var(--color-border);
  }
  html.is-lnb-collapsed .admin-lnb:hover .lnb-section-label,
  html.is-lnb-collapsed .admin-lnb:hover .lnb-item__text,
  html.is-lnb-collapsed .admin-lnb:hover .lnb-item__arrow {
    display: initial;
  }
  html.is-lnb-collapsed .admin-lnb:hover .lnb-sub {
    display: grid;
  }
  html.is-lnb-collapsed .admin-lnb:hover .lnb-item__trigger {
    justify-content: flex-start;
    padding: 10px var(--space-5);
    border-left: 3px solid transparent;
    padding-left: calc(var(--space-5) - 3px);
  }
  html.is-lnb-collapsed .admin-lnb:hover .lnb-item__icon {
    width: 20px;
    height: 20px;
  }
}