/* ==========================================================================
   GET ENGINEERING SEAT — Global Layout Primitives (v1.0)
   Authoritative Reference: docs/05-FRONTEND.md
   ========================================================================== */

/* 1. Containers */
.container {
  width: 100%;
  max-width: var(--container-xl, 1280px);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--spacing-4, 1rem);
  padding-right: var(--spacing-4, 1rem);
}

.container-fluid {
  width: 100%;
  padding-left: var(--spacing-4, 1rem);
  padding-right: var(--spacing-4, 1rem);
}

.container-sm { max-width: var(--container-sm, 640px); }
.container-md { max-width: var(--container-md, 768px); }
.container-lg { max-width: var(--container-lg, 1024px); }

/* 2. Sections */
.section {
  padding-top: var(--spacing-12, 3rem);
  padding-bottom: var(--spacing-12, 3rem);
}

.section-sm {
  padding-top: var(--spacing-6, 1.5rem);
  padding-bottom: var(--spacing-6, 1.5rem);
}

.section-lg {
  padding-top: var(--spacing-20, 5rem);
  padding-bottom: var(--spacing-20, 5rem);
}

/* 3. Grid Utility */
.grid {
  display: grid;
  gap: var(--spacing-6, 1.5rem);
}

.grid-cols-1 { grid-template-columns: repeat(1, minmax(0, 1fr)); }
.grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

/* 4. Flex Utilities */
.flex {
  display: flex;
}

.inline-flex {
  display: inline-flex;
}

.flex-col {
  flex-direction: column;
}

.flex-wrap {
  flex-wrap: wrap;
}

.items-center {
  align-items: center;
}

.items-start {
  align-items: flex-start;
}

.items-end {
  align-items: flex-end;
}

.justify-center {
  justify-content: center;
}

.justify-between {
  justify-content: space-between;
}

.justify-end {
  justify-content: flex-end;
}

.flex-1 {
  flex: 1 1 0%;
}

.flex-shrink-0 {
  flex-shrink: 0;
}

/* 5. Spacing Gaps */
.gap-1 { gap: var(--spacing-1, 0.25rem); }
.gap-2 { gap: var(--spacing-2, 0.5rem); }
.gap-3 { gap: var(--spacing-3, 0.75rem); }
.gap-4 { gap: var(--spacing-4, 1rem); }
.gap-6 { gap: var(--spacing-6, 1.5rem); }
.gap-8 { gap: var(--spacing-8, 2rem); }

/* 6. Alignment & Display Utilities */
.text-center { text-align: center; }
.text-left   { text-align: left; }
.text-right  { text-align: right; }

.block       { display: block; }
.hidden      { display: none !important; }

.w-full      { width: 100%; }
.h-full      { height: 100%; }

/* 7. Accessibility Utility */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

/* 8. Structural Site Shell */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky, 200);
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  transition: background-color var(--transition-base), border-color var(--transition-base);
}

.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.25rem; /* 68px */
  gap: var(--spacing-4);
}

/* Brand Area */
.site-brand {
  display: flex;
  align-items: center;
  gap: var(--spacing-3);
  font-family: var(--font-family-display);
  text-decoration: none !important;
  flex-shrink: 0;
}

.site-brand-logo {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.25rem; /* 36px */
  height: 2.25rem;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: var(--color-primary-contrast);
  font-weight: var(--font-weight-bold);
  font-size: var(--font-size-sm);
  letter-spacing: 0.05em;
  box-shadow: var(--shadow-sm);
  flex-shrink: 0;
}

[data-theme="dark"] .site-brand-logo {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary-dark) 100%);
  color: var(--color-primary-contrast);
}

.site-brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.site-brand-name {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  letter-spacing: -0.01em;
}

[data-theme="dark"] .site-brand-name {
  color: var(--color-heading, #ffffff);
}

.site-brand-tagline {
  font-size: 0.6875rem; /* 11px */
  color: var(--color-text-muted);
  font-weight: var(--font-weight-medium);
  letter-spacing: 0.01em;
  white-space: nowrap;
}

[data-theme="dark"] .site-brand-tagline {
  color: var(--color-text-secondary, #e2e8f0);
}

.site-brand-badge {
  font-size: var(--font-size-xs);
  padding: 2px 6px;
  background-color: var(--color-secondary-light);
  color: var(--color-primary-dark);
  border-radius: var(--radius-sm);
  font-weight: var(--font-weight-bold);
}

/* Primary Desktop Navigation */
.site-nav {
  display: flex;
  align-items: center;
  flex: 1 1 auto;
  justify-content: center;
}

.site-nav-list {
  display: flex;
  align-items: center;
  gap: var(--spacing-5);
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-nav-item {
  display: flex;
  align-items: center;
}

.site-nav-link {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  text-decoration: none !important;
  padding: var(--spacing-2) 0;
  transition: color var(--transition-fast);
  position: relative;
  white-space: nowrap;
}

.site-nav-link:hover,
.site-nav-link.active {
  color: var(--color-primary);
}

[data-theme="dark"] .site-nav-link {
  color: var(--color-text-secondary);
}

[data-theme="dark"] .site-nav-link:hover,
[data-theme="dark"] .site-nav-link.active {
  color: var(--color-teal-bright, #2dd4bf);
}

.site-nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--color-secondary);
  border-radius: var(--radius-full);
}

[data-theme="dark"] .site-nav-link.active::after {
  background-color: var(--color-teal-bright, #2dd4bf);
}

/* Header Actions Area (Search, Saved, Auth, Theme, Mobile Toggle) */
.site-header-actions {
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
  flex-shrink: 0;
}

.site-action-link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-1);
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  text-decoration: none !important;
  padding: var(--spacing-2) var(--spacing-2);
  border-radius: var(--radius-md);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.site-action-link:hover {
  color: var(--color-secondary);
  background-color: var(--color-surface-hover);
}

[data-theme="dark"] .site-action-link {
  color: var(--color-text-secondary);
}

[data-theme="dark"] .site-action-link:hover {
  color: var(--color-teal-bright, #2dd4bf);
  background-color: var(--color-surface-hover);
}

.site-action-label {
  font-weight: var(--font-weight-medium);
}

.site-header-auth {
  display: flex;
  align-items: center;
  gap: var(--spacing-2);
}

#header-dashboard-link,
a#header-dashboard-link {
  background-color: var(--color-secondary, #0d9488) !important;
  color: #ffffff !important;
  font-weight: var(--font-weight-semibold);
  border: 1px solid var(--color-secondary-dark, #0f766e);
  max-width: 160px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

#header-dashboard-link span,
a#header-dashboard-link span {
  color: #ffffff !important;
}

#header-dashboard-link:hover,
a#header-dashboard-link:hover {
  background-color: var(--color-secondary-dark, #0f766e) !important;
  color: #ffffff !important;
}

#header-logout-btn,
button#header-logout-btn {
  border-color: var(--color-border);
  color: var(--color-text);
}

[data-theme="dark"] #header-logout-btn,
[data-theme="dark"] button#header-logout-btn {
  border-color: #475569;
  color: var(--color-text);
}

[data-theme="dark"] #header-logout-btn:hover,
[data-theme="dark"] button#header-logout-btn:hover {
  border-color: var(--color-error);
  color: var(--color-error-text, #f87171);
}

.site-header-divider {
  width: 1px;
  height: 1.5rem; /* 24px */
  background-color: var(--color-border);
  margin: 0 var(--spacing-1);
  flex-shrink: 0;
}

/* Theme Toggle Button - High-Visibility Contrast Control */
.theme-toggle-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem; /* 40px */
  height: 2.5rem;
  border-radius: var(--radius-full);
  border: 1.5px solid var(--color-border-hover);
  background-color: var(--color-surface-hover);
  color: var(--color-primary);
  cursor: pointer;
  padding: 0;
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.08);
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast);
  flex-shrink: 0;
}

.theme-toggle-btn:hover {
  background-color: var(--color-surface-active);
  border-color: var(--color-primary);
  color: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: 0 4px 10px rgba(15, 23, 42, 0.12);
}

.theme-toggle-btn:active {
  transform: translateY(0);
}

.theme-toggle-btn:focus-visible {
  outline: 2px solid var(--color-secondary);
  outline-offset: 2px;
}

[data-theme="dark"] .theme-toggle-btn {
  background-color: rgba(255, 255, 255, 0.08);
  border: 1.5px solid rgba(255, 255, 255, 0.22);
  color: #fbbf24; /* Radiant amber gold */
  box-shadow: 0 0 10px rgba(251, 191, 36, 0.2);
}

[data-theme="dark"] .theme-toggle-btn:hover {
  background-color: rgba(255, 255, 255, 0.16);
  border-color: #fbbf24;
  color: #fef08a;
  box-shadow: 0 0 16px rgba(251, 191, 36, 0.35);
}

.theme-toggle-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.25rem;
  height: 1.25rem;
  line-height: 1;
}

.theme-toggle-icon svg {
  width: 1.125rem;
  height: 1.125rem;
  display: block;
  transition: transform var(--transition-fast);
}

.theme-toggle-btn:hover .theme-toggle-icon svg {
  transform: rotate(15deg);
}

/* Mobile drawer theme toggle styling */
.mobile-theme-btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-2) 0;
  color: var(--color-text);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
}

.mobile-theme-status {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  padding: 3px 10px;
  border-radius: var(--radius-full);
  background-color: var(--color-surface-hover);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
}

/* Mobile Navigation Hamburger Toggle */
.mobile-nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 2.25rem; /* 36px */
  height: 2.25rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background-color: var(--color-surface);
  cursor: pointer;
  padding: 0;
  flex-direction: column;
  gap: 4px;
}

.mobile-nav-toggle:hover {
  background-color: var(--color-surface-hover);
}

.mobile-nav-toggle:focus-visible {
  outline: 2px solid var(--color-secondary);
  outline-offset: 2px;
}

.hamburger-bar {
  display: block;
  width: 18px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: var(--radius-full);
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

/* Mobile Nav Dropdown Menu */
.mobile-nav-menu {
  display: none;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-lg);
  padding: var(--spacing-4) 0;
  max-height: calc(100vh - 4.25rem - 3.75rem);
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

.mobile-nav-menu.is-open {
  display: block;
}

.mobile-nav-menu-inner {
  max-width: var(--container-xl, 1280px);
  margin: 0 auto;
  padding: 0 var(--spacing-4);
}

.mobile-nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-1);
}

.mobile-nav-link {
  display: block;
  padding: var(--spacing-2) var(--spacing-3);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  text-decoration: none !important;
  border-radius: var(--radius-md);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.mobile-nav-link:hover {
  background-color: var(--color-surface-hover);
  color: var(--color-primary);
}

.mobile-nav-divider {
  height: 1px;
  background-color: var(--color-border);
  margin: var(--spacing-2) 0;
  list-style: none;
}

/* Mobile Drawer Auth & Account Area */
.mobile-nav-auth-item {
  list-style: none;
  padding: var(--spacing-1) 0;
}

.mobile-user-profile {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-3);
  padding: var(--spacing-3);
  background-color: var(--color-surface-hover);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}

.mobile-user-info {
  display: flex;
  align-items: center;
  gap: var(--spacing-3);
}

.mobile-user-icon {
  font-size: var(--font-size-xl);
  line-height: 1;
}

.mobile-user-details {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}

.mobile-user-label {
  font-size: 0.6875rem; /* 11px */
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: var(--font-weight-semibold);
}

.mobile-user-email {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.mobile-user-actions {
  display: flex;
  gap: var(--spacing-2);
  width: 100%;
}

.mobile-user-actions .mobile-auth-btn {
  flex: 1;
  text-align: center;
  justify-content: center;
  padding: 0.5rem 0.75rem;
  font-size: var(--font-size-xs);
  min-height: 40px;
}

.mobile-auth-guest {
  display: flex;
  gap: var(--spacing-2);
  padding: var(--spacing-2) 0;
}

.mobile-auth-guest .mobile-auth-btn {
  flex: 1;
  text-align: center;
  justify-content: center;
  min-height: 40px;
}

/* ==========================================================================
   Global Footer Shell
   ========================================================================== */
.site-footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding-top: var(--spacing-16);
  padding-bottom: var(--spacing-12);
  margin-top: auto;
  transition: background-color var(--transition-base), border-color var(--transition-base);
}

.footer-grid,
.site-footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: var(--spacing-8);
  margin-bottom: var(--spacing-8);
}

.footer-col {
  display: flex;
  flex-direction: column;
}

.footer-col-brand {
  padding-right: var(--spacing-4);
}

.footer-brand {
  margin-bottom: var(--spacing-2);
}

.footer-tagline {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: var(--line-height-relaxed);
  margin-bottom: var(--spacing-4);
  max-width: 320px;
}

.footer-badge {
  display: inline-flex;
}

.footer-heading,
.site-footer-heading {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-heading, var(--color-text));
  margin-bottom: var(--spacing-4);
}

.footer-nav-list,
.site-footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-2);
}

.footer-link,
.site-footer-link {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  text-decoration: none !important;
  transition: color var(--transition-fast);
}

.footer-link:hover,
.site-footer-link:hover {
  color: var(--color-primary);
}

[data-theme="dark"] .footer-link:hover,
[data-theme="dark"] .site-footer-link:hover {
  color: var(--color-teal-bright, #2dd4bf);
}

/* Dedicated Admission Disclaimer Card */
.footer-disclaimer {
  background-color: var(--color-surface-hover);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--spacing-4) var(--spacing-5);
  margin-bottom: var(--spacing-8);
}

[data-theme="dark"] .footer-disclaimer {
  background-color: #1e293b;
  border-color: #334155;
}

.footer-disclaimer-text {
  font-size: var(--font-size-xs);
  color: var(--color-text-secondary);
  line-height: var(--line-height-relaxed);
  margin-bottom: 0;
}

.footer-disclaimer-text strong {
  color: var(--color-heading, var(--color-text));
  font-weight: var(--font-weight-semibold);
}

/* Footer Bottom Bar */
.footer-bottom,
.site-footer-bottom {
  padding-top: var(--spacing-6);
  border-top: 1px solid var(--color-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-4);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.footer-copyright {
  margin-bottom: 0;
  color: var(--color-text-muted);
}

[data-theme="dark"] .footer-copyright {
  color: var(--color-text-secondary);
}