/* ==========================================================================
   AI Student Mentor — SaaS Design System
   Modern, responsive, accessible styles for dark and light modes
   ========================================================================== */

:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  
  /* Color Palette — Light Mode */
  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-subtle: #f1f5f9;
  --surface-hover: #f8fafc;
  --border: #e2e8f0;
  --border-focus: #3b82f6;
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-inverse: #ffffff;

  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-light: #eff6ff;
  --primary-border: #bfdbfe;

  --success: #10b981;
  --success-hover: #059669;
  --success-light: #ecfdf5;
  --success-border: #a7f3d0;

  --warning: #f59e0b;
  --warning-light: #fffbeb;
  --warning-border: #fde68a;

  --danger: #ef4444;
  --danger-light: #fef2f2;
  --danger-border: #fecaca;

  --indigo: #6366f1;
  --indigo-light: #eef2ff;

  --purple: #8b5cf6;
  --purple-light: #f5f3ff;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #090d16;
    --surface: #111827;
    --surface-subtle: #1e293b;
    --surface-hover: #1f293d;
    --border: #1f293d;
    --border-focus: #60a5fa;

    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --text-inverse: #0f172a;

    --primary: #3b82f6;
    --primary-hover: #60a5fa;
    --primary-light: rgba(59, 130, 246, 0.15);
    --primary-border: rgba(59, 130, 246, 0.3);

    --success: #34d399;
    --success-light: rgba(52, 211, 153, 0.15);
    --success-border: rgba(52, 211, 153, 0.3);

    --warning: #fbbf24;
    --warning-light: rgba(251, 191, 36, 0.15);
    --warning-border: rgba(251, 191, 36, 0.3);

    --danger: #f87171;
    --danger-light: rgba(248, 113, 113, 0.15);
    --danger-border: rgba(248, 113, 113, 0.3);

    --indigo: #818cf8;
    --indigo-light: rgba(129, 140, 248, 0.15);

    --purple: #a78bfa;
    --purple-light: rgba(167, 139, 250, 0.15);

    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.5);
  }
}

/* Base reset & typography */
*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  background-color: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* Layout Containers */
.site-wrapper {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header.navbar {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 40;
  backdrop-filter: blur(8px);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.15rem;
}

.brand-icon {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--primary), var(--indigo));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 800;
  font-size: 1.1rem;
  box-shadow: 0 2px 4px rgba(37, 99, 235, 0.2);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
  background: var(--primary-light);
}

.nav-user-status {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.user-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.75rem;
  background: var(--surface-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-primary);
  text-decoration: none;
  transition: background var(--transition-fast);
}

.user-pill:hover {
  background: var(--surface-hover);
  border-color: var(--primary-border);
}

.avatar-initial {
  width: 24px;
  height: 24px;
  border-radius: var(--radius-full);
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
}

main.main-content {
  flex: 1;
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

footer.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 1.5rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* Headings & Text */
h1, h2, h3, h4, h5, h6 {
  color: var(--text-primary);
  font-weight: 700;
  margin-top: 0;
  letter-spacing: -0.02em;
}

h1 { font-size: 2.25rem; line-height: 1.25; margin-bottom: 0.5rem; }
h2 { font-size: 1.75rem; line-height: 1.3; margin-bottom: 0.75rem; }
h3 { font-size: 1.25rem; line-height: 1.4; margin-bottom: 0.5rem; }

.lead-text {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.tagline {
  color: var(--text-muted);
  font-size: 1.1rem;
  margin-top: 0;
  margin-bottom: 1.5rem;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-family: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.625rem 1.25rem;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition-fast);
  line-height: 1.2;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
  box-shadow: 0 1px 3px rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
  background: var(--primary-hover);
  border-color: var(--primary-hover);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--surface-subtle);
  color: var(--text-primary);
  border-color: var(--border);
}

.btn-secondary:hover {
  background: var(--surface-hover);
  border-color: var(--text-muted);
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border-color: var(--primary-border);
}

.btn-outline:hover {
  background: var(--primary-light);
  border-color: var(--primary);
}

.btn-sm {
  font-size: 0.85rem;
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
}

.btn-full {
  width: 100%;
}

/* Badges & Chips */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.2rem 0.65rem;
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  font-weight: 600;
  border: 1px solid var(--border);
  background: var(--surface-subtle);
  color: var(--text-secondary);
}

.badge.ok, .badge-success {
  background: var(--success-light);
  color: var(--success);
  border-color: var(--success-border);
}

.badge.bad, .badge-danger {
  background: var(--danger-light);
  color: var(--danger);
  border-color: var(--danger-border);
}

.badge.warning, .badge-warning {
  background: var(--warning-light);
  color: var(--warning);
  border-color: var(--warning-border);
}

.badge-primary {
  background: var(--primary-light);
  color: var(--primary);
  border-color: var(--primary-border);
}

.badge-indigo {
  background: var(--indigo-light);
  color: var(--indigo);
  border-color: transparent;
}

/* Cards & Grid System */
.grid {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  padding: 0;
  list-style: none;
  margin: 1.5rem 0;
}

.grid-cols-2 {
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
}

.grid-cols-3 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-cols-4 {
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast);
  display: flex;
  flex-direction: column;
}

.card-clickable {
  cursor: pointer;
}

.card-clickable:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary-border);
}

.card.selected {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px var(--primary-light), var(--shadow-md);
  background: var(--primary-light);
}

.card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.card-body {
  flex: 1;
}

.card-footer {
  margin-top: 1.25rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

/* Profile Showcase Components */
.profile-hero {
  background: linear-gradient(135deg, var(--surface), var(--surface-subtle));
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.profile-identity {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.profile-avatar-lg {
  width: 72px;
  height: 72px;
  border-radius: var(--radius-full);
  background: linear-gradient(135deg, var(--primary), var(--indigo));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 700;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.25);
  flex-shrink: 0;
}

.profile-info h1 {
  font-size: 1.85rem;
  margin-bottom: 0.25rem;
}

.profile-sub {
  color: var(--text-secondary);
  font-size: 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.stat-pills {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin: 1.5rem 0;
}

.stat-pill-item {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 0.75rem 1.25rem;
  flex: 1;
  min-width: 140px;
}

.stat-pill-item .val {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
  display: block;
}

.stat-pill-item .lbl {
  font-size: 0.8rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
}

/* Chips Container */
.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 0.5rem 0;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--surface-subtle);
  border: 1px solid var(--border);
  padding: 0.3rem 0.7rem;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.chip-level-beginner {
  border-color: #bae6fd;
  color: #0369a1;
  background: #f0f9ff;
}

.chip-level-intermediate {
  border-color: #fde68a;
  color: #b45309;
  background: #fffbeb;
}

.chip-level-advanced {
  border-color: #a7f3d0;
  color: #047857;
  background: #ecfdf5;
}

@media (prefers-color-scheme: dark) {
  .chip-level-beginner {
    border-color: rgba(56, 189, 248, 0.3);
    color: #38bdf8;
    background: rgba(56, 189, 248, 0.1);
  }
  .chip-level-intermediate {
    border-color: rgba(251, 191, 36, 0.3);
    color: #fbbf24;
    background: rgba(251, 191, 36, 0.1);
  }
  .chip-level-advanced {
    border-color: rgba(52, 211, 153, 0.3);
    color: #34d399;
    background: rgba(52, 211, 153, 0.1);
  }
}

/* Filters & Search Toolbar */
.toolbar {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  margin-bottom: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  box-shadow: var(--shadow-sm);
}

.search-box {
  position: relative;
  width: 100%;
}

.search-input {
  width: 100%;
  padding: 0.75rem 1rem 0.75rem 2.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  font-family: inherit;
  font-size: 1rem;
  background: var(--surface-subtle);
  color: var(--text-primary);
  transition: all var(--transition-fast);
}

.search-input:focus {
  outline: none;
  background: var(--surface);
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px var(--primary-light);
}

.search-icon {
  position: absolute;
  left: 0.85rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  pointer-events: none;
  font-size: 1rem;
}

.filter-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.filter-btn {
  background: var(--surface-subtle);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: 0.4rem 0.85rem;
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.filter-btn:hover {
  background: var(--surface-hover);
  color: var(--text-primary);
  border-color: var(--text-muted);
}

.filter-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
  box-shadow: 0 1px 3px rgba(37, 99, 235, 0.3);
}

/* Career Explorer Cards */
.career-card {
  position: relative;
}

.career-card .category-tag {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--primary);
  margin-bottom: 0.35rem;
}

.career-card h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.career-desc {
  font-size: 0.925rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.target-badge {
  position: absolute;
  top: -10px;
  right: 15px;
  background: var(--success);
  color: #fff;
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
  box-shadow: 0 2px 4px rgba(16, 185, 129, 0.3);
}

/* Modal Dialog */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(4px);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-fast);
}

.modal-backdrop.open {
  opacity: 1;
  visibility: visible;
}

.modal-content {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  max-width: 680px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-xl);
  transform: translateY(20px);
  transition: transform var(--transition-normal);
  padding: 2rem;
  position: relative;
}

.modal-backdrop.open .modal-content {
  transform: translateY(0);
}

.modal-close-btn {
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  background: var(--surface-subtle);
  border: 1px solid var(--border);
  border-radius: var(--radius-full);
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.modal-close-btn:hover {
  background: var(--surface-hover);
  color: var(--danger);
}

.modal-section {
  margin-top: 1.5rem;
}

.modal-section h4 {
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

/* Alerts and banners */
.alert {
  padding: 1rem 1.25rem;
  border-radius: var(--radius-md);
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.alert-info {
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid var(--primary-border);
}

.alert-success {
  background: var(--success-light);
  color: var(--success);
  border: 1px solid var(--success-border);
}

.alert-warning {
  background: var(--warning-light);
  color: var(--warning);
  border: 1px solid var(--warning-border);
}

.alert-danger {
  background: var(--danger-light);
  color: var(--danger);
  border: 1px solid var(--danger-border);
}

/* Spinner and Loaders */
.loading-container {
  text-align: center;
  padding: 3rem 1rem;
  color: var(--text-muted);
}

.spinner {
  width: 36px;
  height: 36px;
  border: 3px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto 1rem;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Empty State */
.empty-state {
  text-align: center;
  padding: 3.5rem 1.5rem;
  background: var(--surface);
  border: 1px dashed var(--border);
  border-radius: var(--radius-lg);
  margin: 2rem 0;
}

.empty-state-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  display: block;
}

.empty-state h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

.empty-state p {
  color: var(--text-secondary);
  max-width: 440px;
  margin: 0 auto 1.5rem;
}

/* Landing Page Hero & Features */
.hero-section {
  text-align: center;
  padding: 3rem 1rem 4rem;
  max-width: 800px;
  margin: 0 auto;
}

.hero-section h1 {
  font-size: 3rem;
  line-height: 1.15;
  margin-bottom: 1rem;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 2rem;
}

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 2.5rem;
}

.feature-grid {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  margin: 3rem 0;
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: all var(--transition-fast);
}

.feature-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.35rem;
  margin-bottom: 1rem;
}

.feature-badge-live {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-full);
  background: var(--success-light);
  color: var(--success);
  margin-bottom: 0.5rem;
}

.feature-badge-upcoming {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-full);
  background: var(--surface-subtle);
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

/* Toast Notifications */
.toast {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  background: var(--text-primary);
  color: var(--surface);
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  font-size: 0.9rem;
  font-weight: 500;
  z-index: 200;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transform: translateY(50px);
  opacity: 0;
  transition: all var(--transition-normal);
  pointer-events: none;
}

.toast.show {
  transform: translateY(0);
  opacity: 1;
}

/* Responsive adjustments */
@media (max-width: 640px) {
  .hero-section h1 { font-size: 2.25rem; }
  .nav-container { flex-direction: column; align-items: stretch; }
  .nav-links { justify-content: center; }
  .profile-hero { flex-direction: column; align-items: flex-start; }
}