/* ============================================
   quangit.online — Layout System
   ============================================ */

/* --- App Shell --- */
.app {
  display: flex;
  min-height: 100vh;
}

/* --- Sidebar --- */
.sidebar {
  position: fixed;
  top: 0; left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-right: 1px solid var(--glass-border);
  display: flex;
  flex-direction: column;
  z-index: var(--z-sticky);
  transition: width var(--transition-slow), transform var(--transition-slow);
  overflow: hidden;
}

.sidebar--collapsed {
  width: var(--sidebar-collapsed);
}

.sidebar__brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-5) var(--space-5);
  height: var(--header-height);
  border-bottom: 1px solid var(--border-subtle);
  flex-shrink: 0;
}

.sidebar__logo {
  width: 36px; height: 36px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--primary-500), var(--accent-500));
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--font-bold);
  font-size: var(--text-lg);
  color: white;
  flex-shrink: 0;
}

.sidebar__brand-text {
  font-size: var(--text-md);
  font-weight: var(--font-bold);
  white-space: nowrap;
  overflow: hidden;
  transition: opacity var(--transition-fast);
}

.sidebar--collapsed .sidebar__brand-text {
  opacity: 0;
  width: 0;
}

.sidebar__nav {
  flex: 1;
  padding: var(--space-3);
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.sidebar__section-title {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: var(--space-4) var(--space-3) var(--space-2);
  white-space: nowrap;
  overflow: hidden;
}

.sidebar--collapsed .sidebar__section-title {
  text-align: center;
  font-size: 0;
}

.sidebar--collapsed .sidebar__section-title::after {
  content: '•••';
  font-size: var(--text-xs);
}

.nav-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-size: var(--text-base);
  font-weight: var(--font-medium);
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
  position: relative;
}

.nav-item:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.nav-item--active {
  background: rgba(108, 99, 255, 0.12);
  color: var(--primary-400);
}

.nav-item--active::before {
  content: '';
  position: absolute;
  left: 0; top: 50%;
  transform: translateY(-50%);
  width: 3px; height: 20px;
  background: var(--primary-500);
  border-radius: 0 3px 3px 0;
}

.nav-item__icon {
  width: 20px; height: 20px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.nav-item__text {
  overflow: hidden;
  transition: opacity var(--transition-fast);
}

.sidebar--collapsed .nav-item__text { opacity: 0; width: 0; }
.sidebar--collapsed .nav-item { justify-content: center; padding: var(--space-2); }

.nav-item__badge {
  margin-left: auto;
  min-width: 20px; height: 20px;
  padding: 0 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: var(--font-semibold);
  background: var(--danger-500);
  color: white;
  border-radius: var(--radius-full);
}

.sidebar--collapsed .nav-item__badge { display: none; }

/* Sidebar footer */
.sidebar__footer {
  padding: var(--space-3);
  border-top: 1px solid var(--border-subtle);
  flex-shrink: 0;
}

.sidebar__user {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background var(--transition-fast);
}

.sidebar__user:hover { background: var(--bg-hover); }

.sidebar__user-info {
  overflow: hidden;
  transition: opacity var(--transition-fast);
}

.sidebar--collapsed .sidebar__user-info { opacity: 0; width: 0; }

.sidebar__user-name {
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--text-primary);
}

.sidebar__user-role {
  font-size: var(--text-xs);
  color: var(--text-tertiary);
}

/* Sidebar toggle */
.sidebar__toggle {
  position: absolute;
  top: 50%;
  right: -14px;
  transform: translateY(-50%);
  width: 28px; height: 28px;
  background: var(--bg-elevated);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-secondary);
  font-size: var(--text-sm);
  transition: all var(--transition-fast);
  z-index: 10;
  opacity: 0;
}

.sidebar:hover .sidebar__toggle { opacity: 1; }
.sidebar__toggle:hover { background: var(--primary-500); color: white; border-color: var(--primary-500); }

/* --- Main Content Area --- */
.main {
  flex: 1;
  margin-left: 0;
  transition: margin-left var(--transition-slow);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* Admin layout — push main for sidebar */
.app--admin .main {
  margin-left: var(--sidebar-width);
}

.app--admin.app--sidebar-collapsed .main,
.sidebar--collapsed ~ .main {
  margin-left: var(--sidebar-collapsed);
}

/* --- Header --- */
.header {
  position: sticky;
  top: 0;
  height: var(--header-height);
  background: rgba(10, 10, 26, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-6);
  z-index: var(--z-sticky);
  flex-shrink: 0;
}

.header__left {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.header__title {
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
}

.header__breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--text-sm);
  color: var(--text-tertiary);
}

.header__breadcrumb-sep { color: var(--text-tertiary); }
.header__breadcrumb-current { color: var(--text-primary); font-weight: var(--font-medium); }

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

.header__search {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  width: 240px;
  transition: all var(--transition-fast);
}

.header__search:focus-within {
  border-color: var(--primary-500);
  width: 320px;
  background: var(--bg-hover);
}

.header__search-input {
  flex: 1;
  font-size: var(--text-sm);
  color: var(--text-primary);
}

.header__search-input::placeholder { color: var(--text-tertiary); }

.header__search-icon { color: var(--text-tertiary); flex-shrink: 0; }
.header__search-kbd {
  font-size: 10px;
  padding: 2px 6px;
  background: var(--bg-hover);
  border-radius: 4px;
  color: var(--text-tertiary);
  font-family: var(--font-mono);
}

/* --- Content --- */
.content {
  flex: 1;
  padding: var(--space-6);
}

.content__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-6);
}

.content__title {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
}

.content__subtitle {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  margin-top: var(--space-1);
}

/* --- Grid System --- */
.grid {
  display: grid;
  gap: var(--space-6);
}

.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }

.grid--auto-fill {
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}

/* --- Modal Overlay --- */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-modal);
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-fast);
}

.modal-overlay--open {
  opacity: 1;
  pointer-events: auto;
}

.modal {
  background: var(--bg-elevated);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  width: 90%;
  max-width: 520px;
  max-height: 85vh;
  overflow-y: auto;
  transform: scale(0.95) translateY(10px);
  transition: transform var(--transition-base);
  box-shadow: var(--shadow-xl);
}

.modal-overlay--open .modal {
  transform: scale(1) translateY(0);
}

.modal__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-6);
}

.modal__title {
  font-size: var(--text-xl);
  font-weight: var(--font-bold);
}

.modal__close {
  width: 32px; height: 32px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-tertiary);
  transition: all var(--transition-fast);
}

.modal__close:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.modal__footer {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-3);
  margin-top: var(--space-6);
  padding-top: var(--space-4);
  border-top: 1px solid var(--border-subtle);
}

/* --- Toast Container --- */
.toast-container {
  position: fixed;
  top: var(--space-4);
  right: var(--space-4);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  max-width: 400px;
}

.toast {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-4);
  background: var(--bg-elevated);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  animation: slideInRight var(--transition-base) forwards;
}

.toast--success { border-left: 3px solid var(--success-500); }
.toast--error   { border-left: 3px solid var(--danger-500); }
.toast--warning { border-left: 3px solid var(--warning-500); }
.toast--info    { border-left: 3px solid var(--info-500); }

.toast--exit {
  animation: slideOutRight var(--transition-fast) forwards;
}

.toast__message {
  flex: 1;
  font-size: var(--text-sm);
  color: var(--text-primary);
}

.toast__close {
  color: var(--text-tertiary);
  cursor: pointer;
  padding: 2px;
}

.toast__close:hover { color: var(--text-primary); }

/* --- Responsive --- */
@media (max-width: 1024px) {
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
  .grid--3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    width: var(--sidebar-width);
    z-index: var(--z-overlay);
  }

  .sidebar--mobile-open {
    transform: translateX(0);
  }

  .main {
    margin-left: 0 !important;
  }

  .header__search { display: none; }

  .grid--4,
  .grid--3,
  .grid--2 {
    grid-template-columns: 1fr;
  }

  .content { padding: var(--space-4) var(--space-3); }
  .modal { width: 95%; padding: var(--space-4); max-height: 90vh; }

  /* Content header — stack on mobile */
  .content__header {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-3);
  }
  .content__title { font-size: var(--text-xl); }
  .content__title svg { width: 18px; height: 18px; }

  /* Cards — tighter padding */
  .card { padding: var(--space-4); }
  .card__header { padding: var(--space-3) var(--space-4); }

  /* Tables — horizontal scroll */
  .table-wrapper { overflow-x: auto; -webkit-overflow-scrolling: touch; }

  /* Forms — full width */
  .todo-form__row { flex-direction: column; gap: var(--space-3); }
  .input-group { width: 100%; }

  /* Empty states — smaller */
  .empty-state__icon { font-size: 2rem; }
  .empty-state__icon svg { width: 40px; height: 40px; }

  /* Buttons — touch-friendly */
  .btn { min-height: 40px; font-size: var(--text-sm); }
  .btn--sm { min-height: 34px; }
}

/* --- Mobile menu overlay --- */
.mobile-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: calc(var(--z-overlay) - 1);
}

@media (max-width: 768px) {
  .mobile-overlay--open {
    display: block;
  }
}