body {
  font-family: var(--font-primary);
  color: var(--color-text);
  background:
    radial-gradient(1100px 500px at 85% -5%, color-mix(in srgb, var(--color-primary) 5%, transparent), transparent 60%),
    var(--color-bg);
  background-attachment: fixed;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.app-layout {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: var(--sidebar-width);
  background: var(--sidebar-bg);
  color: var(--sidebar-text);
  box-shadow: var(--sidebar-shadow);
  border-right: 1px solid var(--sidebar-divider);
  padding: var(--space-6) 0;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 100;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

.sidebar-brand {
  padding: 0 var(--space-5);
  margin-bottom: var(--space-4);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.sidebar-brand-text {
  flex: 1;
  min-width: 0;
}

/* Brand wordmark — /img/logo.svg used as a mask so it inherits the brand
   gradient and adapts to themes. Elements using it hold no text; label via
   aria-label. */
.brand-logo {
  display: block;
  width: 128px;
  aspect-ratio: 5083 / 1659;
  background: linear-gradient(135deg, var(--color-primary), #8b5cf6);
  -webkit-mask: url("../img/logo.svg") no-repeat center / contain;
  mask: url("../img/logo.svg") no-repeat center / contain;
}

.sidebar-brand .brand-logo {
  margin: var(--space-1) 0;
}

.sidebar-brand p {
  font-size: var(--text-xs);
  opacity: 0.55;
  margin-top: var(--space-1);
}

/* User avatar area */
.sidebar-user {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-5);
  text-decoration: none;
  color: inherit;
  border-radius: var(--radius-md);
  transition: background 0.15s;
}

a.sidebar-user:hover { background: var(--sidebar-hover-bg); }
a.sidebar-user.active { background: var(--sidebar-active-bg); }

.sidebar-avatar {
  width: 42px;
  height: 42px;
  border-radius: var(--radius-full);
  background: var(--sidebar-avatar-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  font-weight: var(--weight-bold);
  flex-shrink: 0;
  color: var(--sidebar-avatar-text);
  box-shadow: 0 0 0 3px var(--sidebar-avatar-ring);
}

.sidebar-user-info { min-width: 0; }

.sidebar-user-name {
  font-size: 14px;
  font-weight: var(--weight-semibold);
  color: var(--sidebar-text-strong);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.sidebar-user-role {
  font-size: 11px;
  opacity: 0.55;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: var(--weight-medium);
}

/* Dividers */
.sidebar-divider {
  height: 1px;
  background: var(--sidebar-divider);
  margin: var(--space-3) var(--space-5);
}

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

.nav-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
  opacity: 0.75;
}

.sidebar-nav a,
.sidebar-nav-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 9px var(--space-4);
  margin: 2px var(--space-3);
  font-size: 14px;
  font-weight: var(--weight-medium);
  opacity: 0.78;
  transition: background var(--transition), color var(--transition), opacity var(--transition);
  border-radius: var(--radius-md);
}

.sidebar-nav a:hover,
.sidebar-nav-btn:hover {
  opacity: 1;
  background: var(--sidebar-hover-bg);
}

.sidebar-nav a.active {
  opacity: 1;
  background: var(--sidebar-active-bg);
  color: var(--sidebar-active-text);
  font-weight: 600;
  box-shadow: inset 3px 0 0 var(--sidebar-active-border);
}

.sidebar-nav a.active .nav-icon {
  opacity: 1;
}

/* Nav sections — grouped to mirror the curriculum hierarchy */
.sidebar-nav-section + .sidebar-nav-section {
  margin-top: var(--space-2);
}

.sidebar-nav-heading {
  padding: var(--space-2) var(--space-5) var(--space-1);
  font-size: 11px;
  font-weight: var(--weight-semibold);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  opacity: 0.45;
}

/* Admin section */
.sidebar-admin-section { padding: var(--space-1) 0; }

.sidebar-admin-section a {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 9px var(--space-4);
  margin: 2px var(--space-3);
  font-size: 14px;
  font-weight: var(--weight-medium);
  opacity: 0.78;
  transition: background var(--transition), color var(--transition), opacity var(--transition);
  border-radius: var(--radius-md);
}

.sidebar-admin-section a .nav-icon { width: 20px; height: 20px; flex-shrink: 0; opacity: 0.75; }

.sidebar-admin-section a:hover {
  opacity: 1;
  background: var(--sidebar-hover-bg);
}

.sidebar-admin-section a.active {
  opacity: 1;
  background: var(--sidebar-active-bg);
  color: var(--sidebar-active-text);
  font-weight: 600;
  box-shadow: inset 3px 0 0 var(--sidebar-active-border);
}

.sidebar-admin-section a.active .nav-icon { opacity: 1; }

/* Footer */
.sidebar-footer {
  padding: var(--space-3) var(--space-5);
  margin-top: auto;
}

.sidebar-lang {
  display: flex;
  gap: 4px;
  margin-bottom: var(--space-3);
}

.sidebar-lang-btn {
  flex: 1;
  padding: 7px 0;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-align: center;
  border: 1px solid var(--sidebar-divider);
  background: transparent;
  color: var(--sidebar-text);
  opacity: 0.6;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition);
}

.sidebar-lang-btn:hover {
  background: var(--sidebar-hover-bg);
  opacity: 0.9;
}

.sidebar-lang-btn.active {
  background: var(--sidebar-active-bg);
  color: var(--sidebar-active-text);
  border-color: color-mix(in srgb, var(--sidebar-active-border) 40%, transparent);
  opacity: 1;
}

.sidebar-user-actions {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 0;
}

.sidebar-action-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 9px var(--space-4);
  margin: 2px var(--space-3);
  font-size: 14px;
  font-weight: var(--weight-medium);
  opacity: 0.78;
  transition: background var(--transition), color var(--transition), opacity var(--transition);
  border-radius: var(--radius-md);
}

.sidebar-action-btn:hover {
  opacity: 1;
  background: var(--sidebar-hover-bg);
}

.sidebar-action-btn .nav-icon {
  width: 20px;
  height: 20px;
}

.sidebar-nav a:focus-visible,
.sidebar-action-btn:focus-visible,
.sidebar-lang-btn:focus-visible {
  outline: 2px solid var(--sidebar-focus-ring);
  outline-offset: 2px;
}

/* Sidebar collapse toggle */
.sidebar-collapse-btn {
  background: none;
  border: none;
  padding: 6px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  opacity: 0.5;
  transition: opacity 0.2s, background 0.2s;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.sidebar-collapse-btn:hover {
  opacity: 1;
  background: var(--sidebar-hover-bg);
}

.sidebar-collapse-btn .nav-icon {
  width: 20px;
  height: 20px;
  opacity: 1;
  color: var(--sidebar-text-strong);
}

/* Collapsed sidebar */
.sidebar.collapsed {
  width: 64px;
}

.sidebar.collapsed .sidebar-brand-text { display: none; }
.sidebar.collapsed .sidebar-brand { padding: 0 var(--space-3); justify-content: center; }

.sidebar.collapsed .sidebar-user-info { display: none; }
.sidebar.collapsed .sidebar-user { flex-direction: column; align-items: center; padding: var(--space-2); gap: var(--space-1); }

.sidebar.collapsed .sidebar-nav a span { display: none; }
.sidebar.collapsed .sidebar-nav a { justify-content: center; margin: 2px 8px; padding: 10px; }

/* Collapsed: headings become thin dividers so groups stay distinct */
.sidebar.collapsed .sidebar-nav-section + .sidebar-nav-section { margin-top: 0; }
.sidebar.collapsed .sidebar-nav-heading {
  height: 1px;
  margin: var(--space-2) var(--space-3);
  padding: 0;
  font-size: 0;
  line-height: 0;
  overflow: hidden;
  background: var(--sidebar-divider);
}

.sidebar.collapsed .sidebar-admin-section a span { display: none; }
.sidebar.collapsed .sidebar-admin-section a { justify-content: center; margin: 2px 8px; padding: 10px; }

.sidebar.collapsed .sidebar-divider { margin: var(--space-3) var(--space-2); }

.sidebar.collapsed .sidebar-footer { padding: var(--space-3) var(--space-2); }
.sidebar.collapsed .sidebar-lang-btn { padding: 4px 2px; font-size: 10px; }
.sidebar.collapsed .sidebar-user-actions { padding: 0 var(--space-2) var(--space-2); }
.sidebar.collapsed .sidebar-action-btn span { display: none; }
.sidebar.collapsed .sidebar-action-btn { justify-content: center; padding: 6px; }

.sidebar.collapsed .sidebar-nav-btn span { display: none; }
.sidebar.collapsed .sidebar-nav-btn { justify-content: center; margin: 2px 8px; padding: 10px; }

.sidebar.collapsed .sidebar-collapse-btn svg { transform: rotate(180deg); }

/* Collapsed tooltips */
.sidebar.collapsed .sidebar-nav a { position: relative; }
.sidebar.collapsed .sidebar-nav a::after {
  content: attr(data-tooltip);
  position: absolute;
  left: 100%;
  top: 50%;
  transform: translateY(-50%);
  margin-left: 10px;
  padding: 6px 12px;
  background: var(--color-gray-800);
  color: var(--color-bg);
  font-size: 12.5px;
  font-weight: 500;
  border-radius: var(--radius-sm);
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.15s;
  box-shadow: var(--shadow-lg);
  z-index: 200;
}
.sidebar.collapsed .sidebar-nav a:hover::after { opacity: 1; }

.sidebar.collapsed + .main-content,
.app-layout:has(.sidebar.collapsed) .main-content {
  margin-left: 64px;
}

/* Smooth transitions */
.sidebar {
  transition: width 0.25s ease, transform 0.25s ease;
  will-change: transform;
}

.main-content {
  flex: 1;
  min-width: 0;
  margin-left: var(--sidebar-width);
  padding: var(--space-8);
  transition: margin-left 0.25s ease;
}

.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-8);
}

.page-header-title {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
}

.page-header h2 {
  font-size: 1.65rem;
  font-weight: var(--weight-bold);
  letter-spacing: -0.02em;
  color: var(--color-dark-blue);
}

/* Sidebar hide/show toggle (lives inside .page-header-title) */
.sidebar-toggle {
  appearance: none;
  -webkit-appearance: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.6em;
  height: 1.6em;
  padding: 0.25em;
  border-radius: var(--radius-sm);
  border: none;
  background: transparent;
  color: var(--color-gray-500);
  cursor: pointer;
  flex-shrink: 0;
  font-size: var(--text-lg);
  line-height: 1;
  transition: color var(--transition), background var(--transition), transform var(--transition);
}

.sidebar-toggle:hover {
  color: var(--color-primary);
  background: color-mix(in srgb, var(--color-primary) 8%, transparent);
}

.sidebar-toggle:active { transform: scale(0.94); }

.sidebar-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.sidebar-toggle svg {
  width: 100%;
  height: 100%;
  stroke-width: 1;
}

.sidebar-toggle .icon-hidden { display: none; }
body.sidebar-hidden .sidebar-toggle .icon-shown { display: none; }
body.sidebar-hidden .sidebar-toggle .icon-hidden { display: inline-flex; }

/* Dark theme sidebar readability */
[data-theme="dark"] .sidebar-brand p {
  opacity: 0.7;
}

[data-theme="dark"] .sidebar-user-role {
  opacity: 0.65;
}

[data-theme="dark"] .sidebar-nav a,
[data-theme="dark"] .sidebar-nav-btn {
  opacity: 0.85;
}

[data-theme="dark"] .sidebar-admin-section a {
  opacity: 0.85;
}

[data-theme="dark"] .sidebar-lang-btn {
  opacity: 0.7;
}

[data-theme="dark"] .sidebar-action-btn {
  opacity: 0.85;
}

[data-theme="dark"] .sidebar.collapsed .sidebar-nav a::after {
  background: var(--color-light);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

/* Theme toggle (sidebar action) — sun/moon icon swap */
.theme-toggle-action .icon-dark { display: none; }
[data-theme="dark"] .theme-toggle-action .icon-light { display: none; }
[data-theme="dark"] .theme-toggle-action .icon-dark { display: block; }

/* Hidden-sidebar state (desktop only) */
@media (min-width: 769px) {
  body.sidebar-hidden .sidebar {
    transform: translateX(-100%);
    pointer-events: none;
  }
  body.sidebar-hidden .main-content {
    margin-left: 0;
  }
}

.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); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }

.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }

.text-center { text-align: center; }
.text-sm { font-size: var(--text-sm); }
.text-xs { font-size: var(--text-xs); }
.text-muted { color: var(--color-gray-600); }

.hidden { display: none !important; }