/* ==========================================================================
   Pulse Analytics - App Shell Layout
   ==========================================================================
   CSS Grid-based app shell with sidebar, topbar, and scrollable content.
   Responsive: sidebar collapses to overlay below 1024px.
   ========================================================================== */

/* --------------------------------------------------------------------------
   App Grid Shell
   -------------------------------------------------------------------------- */
.app {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  grid-template-rows: var(--topbar-height) 1fr;
  grid-template-areas:
    "sidebar topbar"
    "sidebar content";
  height: 100vh;
  width: 100%;
  overflow: hidden;
}

/* --------------------------------------------------------------------------
   Sidebar
   -------------------------------------------------------------------------- */
.sidebar {
  grid-area: sidebar;
  grid-row: 1 / -1;
  display: flex;
  flex-direction: column;
  background: var(--bg-sidebar);
  color: var(--sidebar-text);
  width: var(--sidebar-width);
  height: 100%;
  overflow: hidden;
  z-index: var(--z-sidebar);
  transition: transform var(--duration-300) var(--ease-out);
}

/* -- Sidebar Header / Logo -- */
.sidebar__header,
.sidebar__brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-5) var(--space-5);
  height: var(--topbar-height);
  flex-shrink: 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.sidebar__logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  color: var(--color-white);
  flex-shrink: 0;
}

.sidebar__logo svg {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
}

.sidebar__logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--color-indigo-400), var(--color-violet-500));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--font-bold);
  font-size: var(--text-md);
  color: var(--color-white);
  flex-shrink: 0;
}

.sidebar__logo-text,
.sidebar__brand-name {
  font-size: var(--text-md);
  font-weight: var(--font-semibold);
  color: var(--color-white);
  letter-spacing: var(--tracking-tight);
}

/* -- Sidebar Navigation -- */
.sidebar__nav {
  flex: 1;
  padding: var(--space-4) var(--space-3);
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.sidebar__section {
  margin-bottom: var(--space-6);
}

.sidebar__section-label {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  text-transform: uppercase;
  letter-spacing: var(--tracking-wider);
  color: var(--sidebar-text-muted);
  padding: var(--space-2) var(--space-3);
  margin-bottom: var(--space-1);
}

.sidebar__link,
.nav__link {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2-5) var(--space-3);
  border-radius: var(--radius-lg);
  color: var(--sidebar-text);
  text-decoration: none;
  font-size: var(--text-base);
  font-weight: var(--font-medium);
  transition: var(--transition-fast);
  position: relative;
}

.sidebar__link:hover,
.nav__link:hover {
  background: var(--sidebar-hover-bg);
  color: var(--sidebar-text-active);
}

.sidebar__link--active,
.nav__link--active {
  background: var(--sidebar-active-bg);
  color: var(--sidebar-text-active);
}

.sidebar__link--active::before,
.nav__link--active::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 20px;
  background: var(--color-indigo-400);
  border-radius: 0 var(--radius-full) var(--radius-full) 0;
}

.sidebar__link-icon,
.nav__icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  opacity: 0.7;
}

.sidebar__link--active .sidebar__link-icon,
.nav__link--active .nav__icon {
  opacity: 1;
}

.sidebar__link-text {
  flex: 1;
  white-space: nowrap;
}

/* Constrain SVGs inside nav links */
.nav__link svg,
.sidebar__link svg {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

.sidebar__link-badge {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  background: var(--color-indigo-500);
  color: var(--color-white);
  padding: 0.125rem 0.5rem;
  border-radius: var(--radius-full);
  min-width: 20px;
  text-align: center;
}

/* Nav list reset (HTML uses ul.nav__list > li.nav__item) */
.nav__list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.nav__item {
  list-style: none;
}

/* -- Sidebar Footer -- */
.sidebar__footer {
  padding: var(--space-4) var(--space-3);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  flex-shrink: 0;
}

.sidebar__user {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-2-5) var(--space-3);
  border-radius: var(--radius-lg);
  transition: var(--transition-fast);
  cursor: pointer;
}

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

.sidebar__user-avatar {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--color-indigo-400), var(--color-violet-500));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  color: var(--color-white);
  flex-shrink: 0;
}

.sidebar__user-info {
  flex: 1;
  min-width: 0;
}

.sidebar__user-name {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-white);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

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

/* --------------------------------------------------------------------------
   Topbar
   -------------------------------------------------------------------------- */
.topbar {
  grid-area: topbar;
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: 0 var(--space-6);
  height: var(--topbar-height);
  background: var(--bg-topbar);
  border-bottom: 1px solid var(--border-default);
  z-index: var(--z-topbar);
}

/* -- Topbar: Hamburger / Menu Button (mobile) -- */
.topbar__hamburger,
.topbar__menu-btn {
  display: none;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-lg);
  color: var(--text-secondary);
  transition: var(--transition-fast);
  cursor: pointer;
  background: none;
  border: none;
  flex-shrink: 0;
}

.topbar__hamburger:hover,
.topbar__menu-btn:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.topbar__hamburger svg,
.topbar__menu-btn svg {
  width: 20px;
  height: 20px;
}

/* -- Topbar: Breadcrumbs (left) -- */
.topbar__left {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

/* -- Topbar: Search (center) -- */
.topbar__center {
  flex: 1;
  max-width: 480px;
  margin: 0 auto;
}

.topbar__search {
  position: relative;
  width: 100%;
}

.topbar__search-icon {
  position: absolute;
  left: var(--space-3);
  top: 50%;
  transform: translateY(-50%);
  width: 16px;
  height: 16px;
  color: var(--text-placeholder);
  pointer-events: none;
}

.topbar__search-input {
  width: 100%;
  padding: var(--space-2) var(--space-3) var(--space-2) var(--space-10);
  background: var(--color-gray-50);
  border: 1px solid transparent;
  border-radius: var(--radius-lg);
  font-size: var(--text-sm);
  color: var(--text-primary);
  transition: var(--transition-fast);
}

.topbar__search-input:hover {
  background: var(--color-gray-100);
}

.topbar__search-input:focus {
  background: var(--color-white);
  border-color: var(--border-focus);
  box-shadow: var(--shadow-focus);
  outline: none;
}

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

.topbar__search-shortcut {
  position: absolute;
  right: var(--space-3);
  top: 50%;
  transform: translateY(-50%);
  font-size: var(--text-xs);
  color: var(--text-tertiary);
  background: var(--color-white);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-sm);
  padding: 0.125rem 0.375rem;
  font-family: var(--font-mono);
  pointer-events: none;
  line-height: 1;
}

/* -- Topbar: Actions (right) -- */
.topbar__right {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  flex-shrink: 0;
}

.topbar__action,
.topbar__notification {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--radius-lg);
  color: var(--text-secondary);
  transition: var(--transition-fast);
  position: relative;
  cursor: pointer;
  background: none;
  border: none;
}

.topbar__action:hover,
.topbar__notification:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.topbar__action svg,
.topbar__notification svg {
  width: 20px;
  height: 20px;
}

.topbar__notification-dot {
  position: absolute;
  top: 7px;
  right: 7px;
  width: 8px;
  height: 8px;
  background: var(--color-red-500);
  border-radius: var(--radius-full);
  border: 2px solid var(--bg-topbar);
}

.topbar__avatar {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--color-indigo-500), var(--color-violet-500));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  color: var(--color-white);
  cursor: pointer;
  transition: var(--transition-fast);
  margin-left: var(--space-2);
}

.topbar__avatar:hover {
  box-shadow: 0 0 0 2px var(--color-indigo-200);
}

/* --------------------------------------------------------------------------
   Main Content Area
   -------------------------------------------------------------------------- */
.main-content {
  grid-area: content;
  padding: var(--content-padding);
  background: var(--bg-app);
  overflow-y: auto;
  overflow-x: hidden;
  min-height: 0;
}

.main-content__inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  width: 100%;
}

/* -- Page Header -- */
.page-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}

.page-header__title {
  font-size: var(--text-2xl);
  font-weight: var(--font-bold);
  color: var(--text-primary);
  letter-spacing: var(--tracking-tight);
}

.page-header__subtitle {
  font-size: var(--text-base);
  color: var(--text-tertiary);
  margin-top: var(--space-1);
}

.page-header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
}

/* --------------------------------------------------------------------------
   Sidebar Mobile Overlay
   -------------------------------------------------------------------------- */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: var(--bg-overlay);
  z-index: calc(var(--z-sidebar) - 1);
  opacity: 0;
  transition: opacity var(--duration-300) var(--ease-default);
}

/* --------------------------------------------------------------------------
   Responsive: Below 1024px
   -------------------------------------------------------------------------- */
@media (max-width: 1023px) {
  .app {
    grid-template-columns: 1fr;
    grid-template-areas:
      "topbar"
      "content";
  }

  .sidebar {
    position: fixed;
    left: 0;
    top: 0;
    bottom: 0;
    transform: translateX(-100%);
    z-index: var(--z-sidebar);
    box-shadow: var(--shadow-2xl);
  }

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

  .sidebar-overlay {
    display: block;
  }

  .sidebar-overlay.sidebar-overlay--visible {
    opacity: 1;
  }

  .topbar__hamburger,
  .topbar__menu-btn {
    display: flex;
  }

  .topbar {
    padding: 0 var(--space-4);
  }

  .topbar__center {
    max-width: none;
  }

  .topbar__search-shortcut {
    display: none;
  }

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

  .page-header {
    flex-direction: column;
    gap: var(--space-3);
  }

  .page-header__actions {
    width: 100%;
  }
}

/* --------------------------------------------------------------------------
   Responsive: Below 640px
   -------------------------------------------------------------------------- */
@media (max-width: 639px) {
  .topbar__center {
    display: none;
  }

  .topbar__right {
    gap: 0;
  }

  .main-content {
    padding: var(--space-3);
  }

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

/* --------------------------------------------------------------------------
   Content Grid Helpers
   -------------------------------------------------------------------------- */
.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));
}

@media (max-width: 1023px) {
  .grid--4 {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (max-width: 639px) {
  .grid--2,
  .grid--3,
  .grid--4 {
    grid-template-columns: 1fr;
  }
}

/* --------------------------------------------------------------------------
   Section Spacing
   -------------------------------------------------------------------------- */
.section {
  margin-bottom: var(--space-6);
}

.section__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.section__title {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--text-primary);
}

.section__action {
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--color-primary);
  cursor: pointer;
  transition: var(--transition-colors);
}

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

/* -- Section Header (alternate HTML pattern) -- */
.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.section-header__title {
  font-size: var(--text-lg);
  font-weight: var(--font-semibold);
  color: var(--text-primary);
}

.section-header__count {
  font-size: var(--text-sm);
  color: var(--text-tertiary);
}