/* ========================================
   Sidebar Navigation Component
   Student Attendance System
   ======================================== */

:root {
  --sidebar-bg: #ffffff;
  --sidebar-dark: #f8f9fa;
  --sidebar-hover: #f0f2f5;
  --sidebar-active: #c0392b;
  --accent: #e74c3c;
  --accent-light: rgba(231, 76, 60, 0.08);
  --text-primary: #1a1a1a;
  --text-muted: #6c757d;
  --text-dim: #495057;
  --sidebar-width: 265px;
  --sidebar-collapsed: 68px;
  --transition: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  --border: rgba(0, 0, 0, 0.08);
}

/* ── Overlay (mobile) ── */
.overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  z-index: 199;
  backdrop-filter: blur(2px);
  transition: opacity var(--transition);
  opacity: 0;
}

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

/* ── Sidebar ── */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background: var(--sidebar-bg);
  display: flex;
  flex-direction: column;
  z-index: 250;
  transition: width var(--transition), transform var(--transition);
  overflow: hidden;
  /* box-shadow: 1px 0 1px rgba(0, 0, 0, 0.06); */
  /* border-right: 1px solid var(--border); */
}

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

/* Brand */
.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 18px;
  border-bottom: 1px solid var(--border);
  min-height: 70px;
  flex-shrink: 0;
  cursor: pointer;
  text-decoration: none;
  color: inherit;
}

.brand-icon {
  width: 36px;
  height: 36px;
  background: var(--accent);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 16px;
  color: #fff;
  box-shadow: 0 4px 14px rgba(231, 76, 60, 0.4);
}

.brand-icon img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}

.brand-text {
  overflow: hidden;
  white-space: nowrap;
}

.brand-text strong {
  display: block;
  color: var(--text-primary);
  font-size: 14.5px;
  font-weight: 700;
  letter-spacing: 0.01em;
}

.brand-text span {
  font-size: 11px;
  color: var(--text-muted);
  font-weight: 400;
}

/* Collapse toggle */
.sidebar-toggle {
  position: absolute;
  top: 22px;
  right: -14px;
  width: 28px;
  height: 28px;
  background: var(--accent);
  border: 2px solid var(--sidebar-bg);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: #fff;
  font-size: 10px;
  z-index: 10;
  transition: transform var(--transition), background var(--transition);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.sidebar-toggle:hover {
  background: #c0392b;
}

.sidebar.collapsed .sidebar-toggle {
  transform: rotate(180deg);
}

/* Scrollable nav area */
.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 14px 0;
  scrollbar-width: thin;
  scrollbar-color: #d1d5db transparent;
}

.sidebar-nav::-webkit-scrollbar {
  width: 4px;
}

.sidebar-nav::-webkit-scrollbar-thumb {
  background: #d1d5db;
  border-radius: 4px;
}

/* Section labels */
.nav-section-label {
  font-size: 10px;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 12px 20px 6px;
  white-space: nowrap;
  overflow: hidden;
  transition: opacity var(--transition);
}

.sidebar.collapsed .nav-section-label {
  opacity: 0;
}

/* Nav items */
.nav-item {
  position: relative;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 13px;
  padding: 10px 18px;
  color: var(--text-dim);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
  border-radius: 0;
  cursor: pointer;
  transition: background var(--transition), color var(--transition), padding var(--transition);
  white-space: nowrap;
  position: relative;
  user-select: none;
}

.nav-link:hover {
  background: var(--sidebar-hover);
  color: var(--text-primary);
}

.nav-link.active {
  background: var(--accent-light);
  color: var(--accent);
  border-right: 3px solid var(--accent);
}

.nav-link.active .nav-icon {
  color: var(--accent);
}

.nav-icon {
  width: 20px;
  font-size: 15px;
  flex-shrink: 0;
  text-align: center;
  color: var(--text-muted);
  transition: color var(--transition);
}

.nav-link:hover .nav-icon {
  color: var(--text-primary);
}

.nav-label {
  flex: 1;
  overflow: hidden;
  white-space: nowrap;
  transition: opacity var(--transition), width var(--transition);
}

.sidebar.collapsed .nav-label {
  opacity: 0;
  width: 0;
}

.sidebar.collapsed .nav-section-label {
  height: 0;
  padding: 0;
}

/* Dropdown chevron */
.nav-chevron {
  font-size: 11px;
  color: var(--text-muted);
  transition: transform var(--transition), opacity var(--transition);
  flex-shrink: 0;
}

.sidebar.collapsed .nav-chevron {
  opacity: 0;
  width: 0;
  overflow: hidden;
}

.nav-link.open .nav-chevron {
  transform: rotate(90deg);
}

/* Badge */
.nav-badge {
  background: var(--accent);
  color: #fff;
  font-size: 10px;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 10px;
  margin-left: auto;
  flex-shrink: 0;
  transition: opacity var(--transition);
}

.sidebar.collapsed .nav-badge {
  opacity: 0;
}

/* Sub-menu (Level 1) */
.sub-menu {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  background: var(--sidebar-dark);
}

.sub-menu.open {
  max-height: 500px;
}

.sub-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 18px 9px 52px;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 13px;
  font-weight: 400;
  cursor: pointer;
  white-space: nowrap;
  transition: background var(--transition), color var(--transition);
  position: relative;
}

.sub-link::before {
  content: '';
  position: absolute;
  left: 37px;
  top: 50%;
  transform: translateY(-50%);
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: #9ca3af;
  transition: background var(--transition);
}

.sub-link:hover {
  background: var(--sidebar-hover);
  color: var(--text-primary);
}

.sub-link:hover::before {
  background: var(--accent);
}

.sub-link.active {
  color: var(--accent);
}

.sub-link.active::before {
  background: var(--accent);
}

/* Sub-sub-menu (Level 2) */
.sub-sub-menu {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.3s ease;
  background: #f8f9fa;
}

.sub-sub-menu.open {
  max-height: 300px;
}

.sub-sub-link {
  display: flex;
  align-items: center;
  padding: 8px 18px 8px 70px;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 12px;
  cursor: pointer;
  white-space: nowrap;
  transition: background var(--transition), color var(--transition);
}

.sub-sub-link:hover {
  color: var(--text-primary);
  background: var(--sidebar-hover);
}

.sub-sub-link.active {
  color: var(--accent);
}

/* Sidebar collapsed – tooltip */
.sidebar.collapsed .nav-link {
  padding: 12px 24px;
  justify-content: center;
}

.sidebar.collapsed .sub-menu {
  display: none;
}

.tooltip-wrap {
  position: relative;
}

.sidebar.collapsed .tooltip-wrap:hover .tooltip-label {
  opacity: 1;
  pointer-events: none;
}

.tooltip-label {
  position: absolute;
  left: calc(var(--sidebar-collapsed) + 6px);
  top: 50%;
  transform: translateY(-50%);
  background: #1a1a1a;
  color: #fff;
  font-size: 12px;
  padding: 5px 10px;
  border-radius: 6px;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.18s;
  z-index: 300;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.2);
}

.tooltip-label::before {
  content: '';
  position: absolute;
  right: 100%;
  top: 50%;
  transform: translateY(-50%);
  border: 5px solid transparent;
  border-right-color: #1a1a1a;
}

/* Sidebar footer */
.sidebar-footer {
  border-top: 1px solid var(--border);
  padding: 14px 18px;
  flex-shrink: 0;
}

.user-card {
  display: flex;
  align-items: center;
  gap: 10px;
  white-space: nowrap;
  overflow: hidden;
}

.sidebar .user-avatar {
  width: 34px;
  height: 34px;
  background: var(--accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 13px;
  color: #fff;
  flex-shrink: 0;
}

.user-info strong {
  display: block;
  font-size: 13px;
  color: var(--text-primary);
}

.user-info span {
  font-size: 11px;
  color: var(--text-muted);
}

.sidebar.collapsed .user-info {
  display: none;
}

/* ── Mobile top bar ── */
.topbar {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 58px;
  background: var(--sidebar-bg);
  align-items: center;
  justify-content: space-between;
  padding: 0 18px;
  z-index: 251;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.08);
  border-bottom: 1px solid var(--border);
}

.topbar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 15px;
}

.topbar-brand .brand-icon {
  width: 30px;
  height: 30px;
  font-size: 13px;
}

.hamburger {
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 20px;
  cursor: pointer;
  padding: 6px;
}

/* ── Main content ── */
.main-content {
  margin-left: var(--sidebar-width);
  flex: 1;
  transition: margin-left var(--transition);
  min-height: 100vh;
  padding: 20px;
  background: #f2f3f5;
  overflow-x: hidden;
  max-width: calc(100vw - var(--sidebar-width));
}

.sidebar.collapsed~.main-content {
  margin-left: var(--sidebar-collapsed);
}

/* Adjust the container to account for sidebar */
body {
  display: flex;
  min-height: 100vh;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .topbar {
    display: flex;
  }

  .sidebar {
    transform: translateX(-100%);
    width: var(--sidebar-width) !important;
  }

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

  .sidebar-toggle {
    display: none;
  }

  .main-content {
    margin-left: 0 !important;
    padding: 68px 16px 16px 16px;
    max-width: 100vw;
  }
}