/* ==========================================================================
   ExamCracker AI - Responsive Layouts & Breakpoints
   ========================================================================== */

/* Mobile Menu Toggle Button (hidden by default) */
.mobile-nav-toggle {
  display: none;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--border-subtle);
  color: #fff;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  font-size: 1.2rem;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}

@media (max-width: 1100px) {
  .dashboard-grid {
    grid-template-columns: 1fr;
  }
  
  .cbt-container {
    grid-template-columns: 1fr;
  }

  .cbt-sidebar-panel {
    order: -1;
  }

  .doubt-solver-layout {
    grid-template-columns: 1fr;
    height: auto;
  }

  .chat-history-sidebar {
    display: none; /* Collapsed on tablet */
  }

  .weakness-heatmap-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 768px) {
  :root {
    --sidebar-width: 260px;
  }

  .mobile-nav-toggle {
    display: flex;
  }

  .app-sidebar {
    transform: translateX(-100%);
    box-shadow: 10px 0 30px rgba(0, 0, 0, 0.7);
  }

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

  .app-main {
    margin-left: 0;
  }

  .app-header {
    padding: 0 16px;
  }

  .page-view {
    padding: 20px 16px;
  }

  .header-right .streak-pill,
  .header-right .xp-pill {
    display: none; /* Save space on mobile */
  }

  .welcome-banner {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }

  .stat-grid {
    grid-template-columns: 1fr;
  }

  .pipeline-steps {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .cbt-action-footer {
    flex-direction: column;
    gap: 16px;
  }

  .footer-left, .footer-right {
    width: 100%;
    justify-content: space-between;
  }
}

/* ==========================================================================
   Mobile Browser Hardening — additive overrides only
   Desktop (1024px+) remains unchanged.
   ========================================================================== */

html {
  box-sizing: border-box;
  max-width: 100%;
  overflow-x: hidden;
}

*, *::before, *::after {
  box-sizing: inherit;
}

img, svg, video, canvas, iframe {
  max-width: 100%;
}

button, input, select, textarea {
  max-width: 100%;
}

@media (max-width: 1023px) {
  html, body {
    width: 100%;
    max-width: 100%;
    overflow-x: hidden;
  }

  body {
    min-width: 320px;
  }

  .app-container {
    width: 100%;
    min-height: 100vh;
    min-height: 100svh;
  }

  .app-sidebar {
    width: min(var(--sidebar-width), 86vw);
    max-width: 320px;
    transform: translateX(-105%);
    transition: transform var(--transition-normal);
    padding-bottom: env(safe-area-inset-bottom);
    z-index: 60;
  }

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

  /* Backdrop without adding a new DOM element. */
  .app-container::before {
    content: '';
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity var(--transition-normal), visibility var(--transition-normal);
    z-index: 55;
  }

  .app-container.sidebar-open::before {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }

  .app-main {
    width: 100%;
    min-width: 0;
    margin-left: 0;
    min-height: 100vh;
    min-height: 100svh;
  }

  .app-header {
    width: 100%;
    min-width: 0;
    height: auto;
    min-height: var(--header-height);
    padding: 10px 16px;
    padding-top: max(10px, env(safe-area-inset-top));
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
  }

  .header-left,
  .header-right {
    min-width: 0;
    flex-wrap: wrap;
  }

  .header-left {
    flex: 1 1 100%;
    gap: 10px;
  }

  .header-right {
    flex: 1 1 100%;
    justify-content: flex-end;
    gap: 8px;
  }

  .mobile-nav-toggle {
    display: inline-flex;
    flex: 0 0 40px;
    min-width: 40px;
    min-height: 40px;
  }

  .exam-picker-wrap {
    min-width: 0;
    max-width: calc(100% - 50px);
    flex: 1 1 auto;
  }

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

  .exam-select {
    min-width: 0;
    max-width: 100%;
    text-overflow: ellipsis;
  }

  .countdown-box {
    flex: 0 1 auto;
    min-width: 0;
  }

  .header-right .btn,
  .header-right .icon-btn,
  .header-right .user-profile-btn {
    min-width: 44px;
    min-height: 44px;
  }

  .header-right .btn {
    max-width: 100%;
  }

  .page-view {
    width: 100%;
    min-width: 0;
    padding: 20px 16px;
    overflow-x: hidden;
  }

  .card,
  .welcome-banner,
  .stat-card,
  .pricing-card,
  .cbt-container,
  .doubt-solver-layout,
  .flashcards-container {
    min-width: 0;
    max-width: 100%;
  }

  .welcome-banner,
  .card-header,
  .score-summary-banner {
    flex-wrap: wrap;
  }

  .card-header {
    gap: 12px;
  }

  .card-title,
  .card-subtitle,
  h1, h2, h3, h4, p, a, span, td, th, label {
    overflow-wrap: break-word;
    word-break: break-word;
  }

  .btn,
  .nav-item,
  .icon-btn,
  .user-profile-btn,
  .mobile-nav-toggle,
  .palette-btn,
  .btn-rating {
    touch-action: manipulation;
  }

  .nav-item {
    min-height: 44px;
  }

  .sidebar-nav {
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    overscroll-behavior: contain;
    min-height: 0;
  }

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

  /* Fluid grids: preserve desktop definitions above 1023px. */
  .dashboard-grid,
  .stat-grid,
  .pricing-grid,
  .options-grid,
  .palette-grid,
  .weakness-heatmap-grid {
    width: 100%;
    min-width: 0;
  }

  .dashboard-grid,
  .stat-grid,
  .pricing-grid,
  .weakness-heatmap-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .pricing-card.featured {
    transform: none;
  }

  .options-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .palette-grid {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 6px;
  }

  /* Toolbars/action rows should wrap rather than create page overflow. */
  .card-header > *,
  .cbt-action-footer > *,
  .footer-left > *,
  .footer-right > *,
  .pipeline-steps > *,
  .modal-actions > * {
    min-width: 0;
  }

  .cbt-action-footer,
  .footer-left,
  .footer-right,
  .pipeline-steps,
  .modal-actions {
    flex-wrap: wrap;
  }

  /* Tables remain usable without expanding the page. */
  .table-responsive,
  .table-wrap,
  .leaderboard-table-wrap {
    width: 100%;
    max-width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    overscroll-behavior-x: contain;
  }

  .leaderboard-table {
    min-width: 620px;
  }

  input,
  select,
  textarea {
    max-width: 100%;
  }

  /* Prevent iOS Safari focus zoom. */
  input,
  select,
  textarea {
    font-size: 16px;
  }

  .modal-overlay.active {
    align-items: center;
    justify-content: center;
    padding: max(16px, env(safe-area-inset-top))
             max(16px, env(safe-area-inset-right))
             max(16px, env(safe-area-inset-bottom))
             max(16px, env(safe-area-inset-left));
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
  }

  .modal-box {
    width: min(620px, 100%);
    max-width: 100%;
    max-height: 90vh;
    max-height: 90dvh;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    overscroll-behavior: contain;
  }

  body.mobile-menu-open {
    overflow: hidden;
    touch-action: none;
  }

  .toast-container {
    right: max(12px, env(safe-area-inset-right));
    bottom: max(12px, env(safe-area-inset-bottom));
    left: max(12px, env(safe-area-inset-left));
  }

  .toast {
    max-width: 100%;
  }
}

@media (min-width: 768px) and (max-width: 1023px) {
  .header-left,
  .header-right {
    flex: 1 1 auto;
  }

  .header-left {
    flex-wrap: nowrap;
  }

  .header-right {
    flex-wrap: nowrap;
  }

  .dashboard-grid,
  .pricing-grid,
  .weakness-heatmap-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 767px) {
  .app-header {
    align-items: stretch;
  }

  .header-left,
  .header-right {
    width: 100%;
  }

  .header-right {
    justify-content: flex-start;
  }

  .exam-picker-wrap {
    flex: 1 1 calc(100% - 50px);
  }

  .countdown-box {
    flex: 1 1 100%;
    justify-content: center;
  }

  .page-view {
    padding: 16px 12px;
  }

  .card {
    padding: 18px;
  }

  .welcome-title {
    font-size: clamp(1.45rem, 7vw, 2rem);
  }

  .pricing-grid {
    grid-template-columns: minmax(0, 1fr);
  }

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

@media (max-width: 390px) {
  .page-view {
    padding-left: 10px;
    padding-right: 10px;
  }

  .card {
    padding: 16px;
  }

  .app-header {
    padding-left: 10px;
    padding-right: 10px;
  }

  .exam-label {
    display: none;
  }

  .exam-picker-wrap {
    max-width: calc(100% - 50px);
  }
}

@supports (height: 100dvh) {
  .app-container,
  .app-main {
    min-height: 100dvh;
  }
}