/* ==========================================================================
   Physics Arcade — responsive layer
   Mobile-first base lives in style.css; this file handles the breakpoints
   and the mobile navigation drawer.
   ========================================================================== */

/* --------------------------------------------------------------------------
   Large desktop and down
   -------------------------------------------------------------------------- */

@media (max-width: 1100px) {
  .main-nav a { padding: .5rem .5rem; font-size: .82rem; }
  .footer-grid { grid-template-columns: 1.4fr repeat(3, 1fr); gap: var(--sp-5); }
}

/* --------------------------------------------------------------------------
   Tablet / small laptop — navigation collapses to a drawer
   -------------------------------------------------------------------------- */

@media (max-width: 960px) {
  :root { --fs-3xl: 2.1rem; --fs-4xl: 2.5rem; --fs-2xl: 1.7rem; }

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

  .main-nav {
    position: fixed;
    inset: var(--header-h) 0 0 auto;
    width: min(320px, 86vw);
    margin: 0;
    background: var(--surface);
    border-left: 1px solid var(--border);
    transform: translateX(100%);
    transition: transform .24s cubic-bezier(.2,.8,.3,1);
    overflow-y: auto;
    padding: var(--sp-4);
    z-index: 110;
  }
  .main-nav.open { transform: translateX(0); }

  .main-nav ul { flex-direction: column; align-items: stretch; gap: 0; }
  .main-nav li { border-bottom: 1px solid var(--border-soft); }
  .main-nav li:last-child { border-bottom: 0; }
  .main-nav a {
    padding: .85rem .6rem;
    font-size: var(--fs-base);
    border-radius: var(--radius-sm);
  }

  .nav-backdrop {
    position: fixed;
    inset: var(--header-h) 0 0 0;
    background: rgba(4,7,14,.6);
    opacity: 0;
    pointer-events: none;
    transition: opacity .22s ease;
    z-index: 105;
  }
  .nav-backdrop.show { opacity: 1; pointer-events: auto; }

  .header-tools { margin-left: auto; }
  .nav-toggle { margin-left: 0; }

  .hero-inner {
    grid-template-columns: 1fr;
    gap: var(--sp-6);
    padding: var(--sp-7) var(--sp-4);
  }
  .hero-visual { order: -1; aspect-ratio: 16 / 10; }

  .grid-4 { grid-template-columns: repeat(2, minmax(0,1fr)); }
  .grid-3 { grid-template-columns: repeat(2, minmax(0,1fr)); }

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

/* --------------------------------------------------------------------------
   Phone landscape / small tablet
   -------------------------------------------------------------------------- */

@media (max-width: 768px) {
  :root { --sp-7: 2.25rem; --sp-8: 2.75rem; }

  .section { padding: var(--sp-6) 0; }

  .grid-auto { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }

  .article-body { font-size: 1rem; }
  .toc { position: static; }

  .game-layout { grid-template-columns: 1fr; }
  .game-aside { position: static; }

  .author-box { flex-direction: column; }
  .hero-stats { gap: var(--sp-4); }
}

/* --------------------------------------------------------------------------
   Phone portrait
   -------------------------------------------------------------------------- */

@media (max-width: 560px) {
  :root { --fs-3xl: 1.85rem; --fs-2xl: 1.5rem; --fs-xl: 1.28rem; }

  .wrap { padding-inline: var(--sp-3); }

  .grid-4, .grid-3, .grid-2 { grid-template-columns: 1fr; }
  .grid-auto { grid-template-columns: 1fr; }

  .hero-actions { flex-direction: column; align-items: stretch; }
  .hero-actions .btn { width: 100%; }

  .section-head { flex-direction: column; align-items: flex-start; }

  .filter-grid { grid-template-columns: 1fr; }
  .filter-foot { flex-direction: column; align-items: stretch; }

  .footer-grid { grid-template-columns: 1fr; gap: var(--sp-5); }

  .brand-name span { font-size: .98rem; }

  .hero-stats { gap: var(--sp-3) var(--sp-5); }

  .ad-slot { margin: var(--sp-5) auto; }
}

/* --------------------------------------------------------------------------
   Very narrow (320px) — nothing may overflow horizontally
   -------------------------------------------------------------------------- */

@media (max-width: 380px) {
  :root { --fs-3xl: 1.65rem; --fs-2xl: 1.38rem; }
  .wrap { padding-inline: var(--sp-3); }
  .btn { padding: .65rem 1rem; }
  .brand-name small { display: none; }
  .card-body { padding: var(--sp-3); }
  .hud-row { gap: var(--sp-2); }
  .hud-stat strong { font-size: 1rem; }
}

/* --------------------------------------------------------------------------
   Landscape phones — keep the game stage usable
   -------------------------------------------------------------------------- */

@media (max-height: 520px) and (orientation: landscape) {
  .site-header { position: static; }
  .game-stage { max-height: none; }
  .game-frame { max-height: 82vh; }
}

/* --------------------------------------------------------------------------
   Wide screens
   -------------------------------------------------------------------------- */

@media (min-width: 1400px) {
  :root { --wrap: 1260px; }
}