/* Mobile & tablet — cross-browser (Safari iOS, Chrome Android, Firefox) */

/* Safer viewport on notched devices */
@supports (padding: env(safe-area-inset-top)) {
  .site-nav {
    padding-left: env(safe-area-inset-left);
    padding-right: env(safe-area-inset-right);
    padding-top: env(safe-area-inset-top);
  }
  .mobile-menu {
    padding-left: env(safe-area-inset-left);
    padding-right: env(safe-area-inset-right);
    padding-bottom: env(safe-area-inset-bottom);
  }
  .container {
    padding-left: max(var(--space-lg), env(safe-area-inset-left));
    padding-right: max(var(--space-lg), env(safe-area-inset-right));
  }
}

body.nav-open {
  overflow: hidden;
  position: fixed;
  width: 100%;
  height: 100%;
}

/* ─── Tablet (≤1024px) ─────────────────────────────────────────── */
@media (max-width: 1024px) {
  :root {
    --nav-height: 52px;
  }

  .mobile-menu {
    top: 52px;
    z-index: calc(var(--z-nav) + 10);
    -webkit-overflow-scrolling: touch;
    overscroll-behavior: contain;
  }

  .content-layout {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
    min-width: 0;
  }

  .page-content {
    min-width: 0;
    overflow-x: hidden;
  }

  /* Horizontal scroll section nav on content pages */
  .page-sidebar {
    position: sticky;
    top: calc(var(--nav-height) + var(--space-sm));
    z-index: 50;
    margin: 0 calc(-1 * var(--space-lg));
    padding: 0 var(--space-lg) var(--space-sm);
    background: linear-gradient(var(--bg-primary) 70%, transparent);
  }

  .sidebar-nav {
    display: flex;
    flex-direction: row;
    flex-wrap: nowrap;
    gap: 0.35rem;
    overflow-x: auto;
    overflow-y: hidden;
    -webkit-overflow-scrolling: touch;
    scroll-snap-type: x proximity;
    scrollbar-width: thin;
    padding: var(--space-sm);
  }

  .sidebar-nav h4 {
    display: none;
  }

  .sidebar-nav a {
    flex: 0 0 auto;
    white-space: nowrap;
    scroll-snap-align: start;
    border-left: none;
    border: 1px solid var(--border-color);
    padding: 0.5rem 0.75rem;
    font-size: 0.75rem;
  }

  .topic-block {
    scroll-margin-top: calc(var(--nav-height) + 4.5rem);
  }

  .benchmark-integration {
    padding: var(--space-lg);
  }

  .benchmark-integration-header .btn {
    width: 100%;
    justify-content: center;
  }

  .architecture-viewer .diagram-inner {
    min-height: 220px;
    padding: var(--space-md);
  }
}

/* ─── Phone (≤768px) ───────────────────────────────────────────── */
@media (max-width: 768px) {
  html {
    font-size: 15px;
  }

  .container {
    padding-left: var(--space-md);
    padding-right: var(--space-md);
  }

  .section {
    padding: var(--space-2xl) 0;
  }

  .section-header {
    margin-bottom: var(--space-xl);
  }

  .section-header p {
    font-size: 0.9375rem;
  }

  /* Home hero */
  .home-hero {
    min-height: auto !important;
    display: block !important;
  }

  .hero-content {
    padding: var(--space-2xl) 0 var(--space-xl);
  }

  .hero-cta {
    flex-direction: column;
    align-items: stretch;
    width: 100%;
    max-width: 360px;
    margin-left: auto;
    margin-right: auto;
  }

  .hero-cta .btn {
    width: 100%;
    justify-content: center;
    min-height: 48px;
  }

  .page-hero {
    padding: var(--space-xl) 0 var(--space-lg);
  }

  .page-hero .hero-subtitle {
    text-align: left;
    font-size: 1rem;
  }

  .page-hero h1 {
    font-size: clamp(1.65rem, 7vw, 2.25rem);
    word-break: break-word;
  }

  /* Learning path */
  .learning-path {
    flex-direction: column;
    align-items: stretch;
    gap: var(--space-xs);
  }

  .path-node {
    flex-direction: column;
    align-items: stretch;
  }

  .path-arrow {
    display: none;
  }

  .path-step {
    display: block;
    text-align: center;
    min-height: 44px;
    line-height: 1.35;
    padding: var(--space-md);
  }

  /* Timeline */
  .timeline {
    padding-left: var(--space-xl);
  }

  .timeline-item::before {
    left: calc(-1 * var(--space-xl) + 2px);
  }

  /* Knowledge graph */
  .knowledge-graph {
    padding: var(--space-md);
    gap: var(--space-xs);
  }

  .kg-connector {
    display: none;
  }

  .kg-node {
    font-size: 0.75rem;
    padding: 0.4rem 0.6rem;
  }

  /* Topic headings */
  .topic-block h2 {
    flex-wrap: wrap;
    align-items: flex-start;
    font-size: 1.35rem;
    gap: var(--space-sm);
  }

  .bookmark-btn {
    min-width: 44px;
    min-height: 44px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .content-deep-dive,
  .content-practical {
    padding: var(--space-md);
  }

  .pros-cons {
    grid-template-columns: 1fr;
  }

  /* Tables */
  .table-responsive {
    width: 100%;
    max-width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    margin: var(--space-md) 0;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
  }

  .table-responsive .data-table {
    margin: 0;
    min-width: 520px;
    font-size: 0.75rem;
  }

  .table-responsive .data-table th,
  .table-responsive .data-table td {
    padding: 0.5rem 0.65rem;
  }

  /* Diagrams & equations */
  .diagram-container,
  .architecture-viewer {
    padding: var(--space-sm);
  }

  .equation-display {
    font-size: 0.9rem;
    padding: var(--space-sm);
    word-break: break-word;
  }

  .eq-legend {
    font-size: 0.75rem;
  }

  pre {
    font-size: 0.7rem;
    padding: var(--space-md);
  }

  /* Benchmark block */
  .benchmark-integration-header {
    flex-direction: column;
    align-items: stretch;
  }

  .benchmark-integration-header .btn {
    width: 100%;
  }

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

  .benchmark-stat-card .stat-value {
    font-size: 1.5rem;
  }

  /* Feature cards */
  .feature-card {
    padding: var(--space-lg);
  }

  /* Footer */
  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }

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

  .back-to-top {
    bottom: max(var(--space-md), env(safe-area-inset-bottom, 0px));
    right: var(--space-md);
    width: 44px;
    height: 44px;
  }

  /* Author page */
  .author-hero {
    grid-template-columns: 1fr;
    text-align: center;
    justify-items: center;
  }

  .author-highlights {
    grid-template-columns: 1fr;
  }

  .author-hero .btn {
    width: 100%;
    max-width: 280px;
    justify-content: center;
  }

  .resource-hub-grid {
    grid-template-columns: 1fr;
  }

  /* Lifecycle (agentic page) */
  .lifecycle-ring {
    grid-template-columns: 1fr;
    max-width: 280px;
  }

  .lifecycle-step {
    aspect-ratio: auto;
    border-radius: var(--radius-lg);
    min-height: 72px;
  }

  .token-journey {
    flex-direction: column;
    gap: var(--space-sm);
  }

  .token-arrow {
    transform: rotate(90deg);
  }

  /* Touch targets */
  .icon-btn,
  .nav-toggle {
    min-width: 44px;
    min-height: 44px;
  }

  .nav-logo-icon {
    width: 36px;
    height: 36px;
  }

  .mobile-menu a {
    min-height: 48px;
    display: flex;
    align-items: center;
  }

  .external-hub-card .btn {
    width: 100%;
    justify-content: center;
  }
}

/* ─── Small phone (≤400px) ─────────────────────────────────────── */
@media (max-width: 400px) {
  .nav-logo span:not(.nav-logo-icon) {
    font-size: 1rem;
  }

  .breadcrumb {
    font-size: 0.75rem;
  }
}