/* YK 24.2 - Mobile/iPhone refinements. */
html, body {
  max-width: 100%;
  overflow-x: hidden;
}

@supports (min-height: 100dvh) {
  body,
  .shell,
  .login-page {
    min-height: 100dvh;
  }
}

@media (max-width: 960px) {
  html {
    scroll-padding-top: calc(72px + env(safe-area-inset-top, 0px));
  }

  .topbar {
    min-height: 64px;
    height: auto;
    padding-top: max(8px, env(safe-area-inset-top, 0px));
    padding-left: max(14px, env(safe-area-inset-left, 0px));
    padding-right: max(14px, env(safe-area-inset-right, 0px));
  }

  .content {
    padding-left: max(20px, env(safe-area-inset-left, 0px));
    padding-right: max(20px, env(safe-area-inset-right, 0px));
    padding-bottom: max(28px, env(safe-area-inset-bottom, 0px));
  }

  .sidebar {
    height: 100vh;
    height: 100dvh;
    padding-top: max(18px, env(safe-area-inset-top, 0px));
    padding-bottom: max(16px, env(safe-area-inset-bottom, 0px));
  }

  .mobile-menu {
    width: 44px;
    height: 44px;
    flex: 0 0 auto;
  }

  .breadcrumb {
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .study-layout,
  .study-layout .panel,
  .chat-panel {
    min-width: 0;
  }

  .chat {
    height: clamp(320px, 58dvh, 560px);
    min-height: 320px;
    max-height: none;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
  }

  .compose-row textarea,
  .field input,
  .search,
  .toc-search {
    font-size: 16px;
  }

  .compose-row textarea {
    line-height: 1.45;
    min-height: 48px;
  }

  .send-btn {
    width: 48px;
    height: 48px;
  }

  .tab-btn,
  .primary-btn,
  .secondary-btn,
  .add-subject-btn,
  .logout-btn {
    min-height: 44px;
  }

  .quick-questions {
    scroll-snap-type: x proximity;
    -webkit-overflow-scrolling: touch;
  }

  .chip {
    min-height: 36px;
    scroll-snap-align: start;
  }
}

@media (max-width: 620px) {
  .content {
    padding-left: max(14px, env(safe-area-inset-left, 0px));
    padding-right: max(14px, env(safe-area-inset-right, 0px));
    padding-bottom: max(24px, env(safe-area-inset-bottom, 0px));
  }

  .topbar {
    padding-left: max(10px, env(safe-area-inset-left, 0px));
    padding-right: max(10px, env(safe-area-inset-right, 0px));
  }

  .topbar-badge {
    display: none;
  }

  .chat {
    height: clamp(280px, 52dvh, 480px);
    min-height: 280px;
  }

  .chat-compose {
    padding-bottom: max(13px, env(safe-area-inset-bottom, 0px));
  }

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

  .subject-header h1 {
    overflow-wrap: anywhere;
  }
}

/* YK 27.8 - Logged-in responsive shell for iPad/tablet and phones.
   iPad Safari may expose a wider desktop-style viewport, so coarse touch devices
   up to 1366px are treated as tablets too. */
@media (max-width: 1180px), (max-width: 1366px) and (hover: none) and (pointer: coarse) {
  .shell {
    display: block !important;
    grid-template-columns: 1fr !important;
    width: 100% !important;
    min-width: 0 !important;
  }

  .main {
    width: 100% !important;
    min-width: 0 !important;
  }

  .sidebar {
    position: fixed !important;
    top: 0 !important;
    left: 0 !important;
    transform: translateX(-105%) !important;
    z-index: 30 !important;
    width: min(340px, 84vw) !important;
    height: 100vh !important;
    height: 100dvh !important;
    padding-top: max(18px, env(safe-area-inset-top, 0px));
    padding-bottom: max(16px, env(safe-area-inset-bottom, 0px));
    box-shadow: 18px 0 60px rgba(2,6,23,.22);
    transition: transform .24s ease !important;
  }

  .sidebar.open {
    left: 0 !important;
    transform: translateX(0) !important;
  }

  .sidebar-overlay {
    position: fixed;
    inset: 0;
    z-index: 20;
    background: rgba(2,6,23,.42);
    backdrop-filter: blur(2px);
  }

  .mobile-menu {
    display: grid !important;
    place-items: center;
    width: 44px;
    height: 44px;
    flex: 0 0 auto;
  }

  .topbar {
    width: 100% !important;
    min-height: 68px;
    height: auto;
    padding: max(8px, env(safe-area-inset-top, 0px)) max(22px, env(safe-area-inset-right, 0px)) 8px max(22px, env(safe-area-inset-left, 0px));
  }

  .breadcrumb {
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .content {
    width: 100% !important;
    max-width: none !important;
    margin: 0 !important;
    padding: 28px max(26px, env(safe-area-inset-right, 0px)) 42px max(26px, env(safe-area-inset-left, 0px));
  }

  .page-head {
    align-items: flex-start;
    gap: 18px;
  }

  .page-head > div:first-child {
    min-width: 0;
  }

  .page-head h1 {
    font-size: clamp(30px, 4.2vw, 40px);
  }

  .dashboard-actions {
    width: min(46%, 480px);
    min-width: 340px;
    align-self: flex-start;
  }

  .dashboard-actions .search {
    min-width: 0;
    flex: 1 1 auto;
  }

  .subject-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr)) !important;
    gap: 16px;
  }

  .subject-card {
    min-height: 200px;
    padding: 20px;
  }

  .subject-card h3 {
    font-size: 19px;
  }

  .catalog-section + .catalog-section {
    margin-top: 26px;
  }

  .study-layout {
    grid-template-columns: 1fr !important;
  }

  .chat-panel {
    position: static;
  }

  .mobile-tabs {
    display: flex;
  }

  .study-layout .panel {
    display: none;
  }

  .study-layout .panel.mobile-active {
    display: block;
  }

  .knowledge {
    max-height: none;
  }
}

@media (max-width: 760px) {
  .topbar {
    min-height: 62px;
    padding-left: max(12px, env(safe-area-inset-left, 0px));
    padding-right: max(12px, env(safe-area-inset-right, 0px));
  }

  .mobile-menu {
    width: 42px;
    height: 42px;
  }

  .content {
    padding: 20px max(14px, env(safe-area-inset-right, 0px)) max(28px, env(safe-area-inset-bottom, 0px)) max(14px, env(safe-area-inset-left, 0px));
  }

  .page-head {
    display: block;
    margin-bottom: 22px;
  }

  .page-head h1 {
    font-size: clamp(27px, 8vw, 34px);
    line-height: 1.08;
  }

  .page-head p {
    font-size: 14px;
    line-height: 1.5;
  }

  .dashboard-actions {
    display: grid;
    grid-template-columns: 1fr;
    width: 100%;
    min-width: 0;
    margin-top: 16px;
    gap: 10px;
  }

  .dashboard-actions .search {
    width: 100%;
    margin: 0;
  }

  .add-subject-btn {
    width: 100%;
  }

  .catalog-head {
    display: flex;
    align-items: flex-start;
    gap: 12px;
  }

  .catalog-head > div {
    min-width: 0;
  }

  .catalog-count {
    margin-top: 0;
  }

  .subject-grid {
    grid-template-columns: 1fr !important;
    gap: 12px;
  }

  .subject-card {
    min-height: 0;
    padding: 18px;
  }

  .subject-icon {
    width: 48px;
    height: 48px;
    border-radius: 14px;
    font-size: 24px;
  }

  .subject-card h3 {
    margin-top: 14px;
    font-size: 19px;
  }

  .subject-card p {
    font-size: 13px;
    line-height: 1.5;
  }

  .card-action {
    padding-top: 16px;
  }
}

@media (max-width: 420px) {
  .breadcrumb {
    max-width: 210px;
    font-size: 12px;
  }

  .catalog-head {
    display: block;
  }

  .catalog-count {
    display: inline-flex;
    margin-top: 10px;
  }
}