/* =========================================================================
   Corera Tech LLC — responsive rules
   Breakpoints: 1100 / 900 (nav collapse) / 640 / 420
   ========================================================================= */

@media (max-width: 1100px) {
  .lattice { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .cards { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .steps { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .approach { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .info-grid.cols-3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-grid { grid-template-columns: minmax(0, 1.6fr) repeat(3, minmax(0, 1fr)); gap: 2rem; }
  .hero-inner { grid-template-columns: minmax(0, 6fr) minmax(0, 5fr); }
}

@media (max-width: 900px) {
  /* ---- Navigation collapses ---- */
  .nav-toggle { display: inline-flex; }

  /* Absolute (not fixed): the header's backdrop-filter makes it the containing block. */
  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    height: calc(100vh - 74px);
    height: calc(100dvh - 74px);
    z-index: 49;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 0;
    padding: 0.75rem var(--gutter) 2rem;
    background: var(--ink);
    border-top: 1px solid var(--line-dark);
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.25s var(--ease), transform 0.3s var(--ease), visibility 0s linear 0.3s;
  }
  body.nav-open .site-nav {
    opacity: 1;
    visibility: visible;
    transform: none;
    transition: opacity 0.25s var(--ease), transform 0.3s var(--ease), visibility 0s;
  }
  body.nav-open { overflow: hidden; }

  .nav-list { flex-direction: column; gap: 0; }
  .nav-list li { border-bottom: 1px solid var(--line-dark); }
  .nav-list a {
    display: block;
    padding: 1.05rem 0.25rem;
    font-size: 1.15rem;
    font-weight: 500;
    color: var(--paper);
    border-radius: 0;
  }
  .nav-list a[aria-current="page"]::after {
    left: auto;
    right: 0.25rem;
    top: 50%;
    bottom: auto;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    transform: translateY(-50%);
  }
  .nav-cta { margin-top: 1.5rem; }
  .nav-cta .btn { width: 100%; padding: 1rem; font-size: 1rem; }

  /* ---- Layouts stack ---- */
  .hero { padding-top: clamp(4rem, 10vw, 6rem); }
  .hero-inner { grid-template-columns: minmax(0, 1fr); gap: 2.5rem; }
  .hero-copy { padding-bottom: 0; }
  .hero-title { max-width: 14ch; }
  .hero-panel { margin-bottom: -72px; }
  .after-hero { padding-top: calc(72px + var(--section)); }

  .page-hero-inner { grid-template-columns: minmax(0, 1fr); gap: 2rem; align-items: start; }
  .page-meta { border-left: 0; border-top: 1px solid var(--line-strong); padding-left: 0; padding-top: 1.25rem; grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .split { grid-template-columns: minmax(0, 1fr); gap: 2rem; }

  .feature-row { grid-template-columns: minmax(0, 1fr); gap: 2rem; }
  .feature-row.reverse .feature-copy { order: 0; }

  .cta-band { grid-template-columns: minmax(0, 1fr); }
  .cta-actions { justify-content: flex-start; }

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

  .contact-grid { grid-template-columns: minmax(0, 1fr); }
  .contact-card { position: static; }

  .legal-layout { grid-template-columns: minmax(0, 1fr); }
  .legal-aside { position: static; order: -1; }
  .toc ol { grid-template-columns: repeat(2, minmax(0, 1fr)); }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 2.5rem 2rem; }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 640px) {
  :root { --section: clamp(56px, 12vw, 80px); }

  body { font-size: 1rem; }

  .header-inner { height: 66px; }
  .site-nav { height: calc(100vh - 66px); height: calc(100dvh - 66px); }
  .brand-mark { width: 26px; height: 26px; }
  .brand-word { font-size: 0.85rem; }

  .hero-title { font-size: clamp(2.5rem, 12vw, 3.4rem); }
  .hero-actions .btn { flex: 1 1 auto; }
  .hero-meta { gap: 0.4rem 1.25rem; }

  .panel-item { grid-template-columns: 40px 1fr; padding: 0.9rem 1.15rem; }
  .panel-item .icon-go { display: none; }
  .panel-head, .panel-foot { padding-inline: 1.15rem; }
  .panel-foot { flex-direction: column; gap: 0.25rem; }

  .lattice { grid-template-columns: minmax(0, 1fr); border-radius: var(--radius); }
  .lattice-card { min-height: 0; padding: 1.6rem 1.35rem; }
  .card-top { margin-bottom: 1.75rem; }
  .card-ghost { font-size: 5.5rem; }

  .cards { grid-template-columns: minmax(0, 1fr); }
  .card { padding: 1.5rem; }
  .steps { grid-template-columns: minmax(0, 1fr); }
  .approach { grid-template-columns: minmax(0, 1fr); }
  .check-list { grid-template-columns: minmax(0, 1fr); }

  .info-grid, .info-grid.cols-3 { grid-template-columns: minmax(0, 1fr); gap: 1.1rem; }
  .info-panel { border-radius: var(--radius); }

  .page-meta { grid-template-columns: minmax(0, 1fr); }
  .page-hero-title { font-size: clamp(2.2rem, 10vw, 3rem); }

  .flow { padding-inline: 1.15rem; }
  .mock-chips { padding-inline: 1.15rem; }

  .cta-band { padding: 2rem 1.5rem; border-radius: var(--radius); }
  .cta-actions .btn { flex: 1 1 auto; }

  .form-row { grid-template-columns: minmax(0, 1fr); }
  .contact-form, .contact-card { border-radius: var(--radius); }
  .form-foot .btn { width: 100%; }

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

  .footer-grid { grid-template-columns: minmax(0, 1fr); gap: 2rem; }
  .site-footer { padding-top: 3.25rem; }
  .footer-bottom { flex-direction: column; gap: 0.35rem; }
}

@media (max-width: 420px) {
  .btn { padding: 0.9rem 1.15rem; }
  .hero-title { font-size: clamp(2.3rem, 13vw, 3rem); }
  .lattice-card h3 { font-size: 1.15rem; }
}

/* ---- Print: keep it readable and ink-light ---- */
@media print {
  .site-header, .site-footer, .nav-toggle, .cta-band, .hero-grid-lines, .skip-link { display: none !important; }
  body { background: #fff; color: #000; }
  .hero, .section-dark, .contact-card { background: #fff !important; color: #000 !important; }
  .hero-title, .section-dark h2, .contact-card h2 { color: #000 !important; }
  a { text-decoration: underline; }
}