/*
  responsive.css — Mobile-first breakpoint system
  Board directives:
    Jony Ive:  "one vital at a time on mobile, not four crammed in"
    John Maeda: "one number, one colour, one action on mobile"
    Rasmus: "touch targets 44px minimum"
  
  Breakpoints:
    xs:  320px  (small phone)
    sm:  480px  (large phone)
    md:  768px  (tablet)
    lg:  1024px (laptop)
    xl:  1280px (desktop — this is the default design width)
*/

/* ── Utilities ───────────────────────────────────────────── */
.hide-mobile  { display: block; }
.show-mobile  { display: none; }
.hide-tablet  { display: block; }

/* ── xl: 1280px+ (default — already handled in base.css) ─── */

/* ── lg: 1024px ──────────────────────────────────────────── */
@media (max-width: 1024px) {
  :root { --page-padding: 36px; }

  .hero__body { grid-template-columns: 1fr 1fr; gap: var(--space-8); }
  .hero__left { padding-right: var(--space-8); }
  .hero__right { padding-left: var(--space-8); }

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

  .experiment { gap: var(--space-10); }
  .progress-numbers { grid-template-columns: 1fr 1fr; }
  .platform-grid { grid-template-columns: 1fr 1fr; }

  /* Character page */
  .pillars-grid { grid-template-columns: repeat(3, 1fr); }
}

/* ── md: 768px (tablet) ──────────────────────────────────── */
@media (max-width: 768px) {
  :root { --page-padding: 24px; --nav-height: 56px; }

  /* Nav — collapse links, keep brand + status */
  .nav__links { display: none; }
  .nav__mobile-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px; height: 36px;
    border: 1px solid var(--border);
    cursor: pointer;
    color: var(--text-muted);
    font-size: 16px;
    background: transparent;
  }

  /* Mobile nav drawer */
  .nav__drawer {
    position: fixed;
    top: var(--nav-height);
    left: 0; right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: var(--space-4) var(--page-padding);
    z-index: calc(var(--z-nav) - 1);
    display: none;
    flex-direction: column;
    gap: var(--space-4);
  }
  .nav__drawer.open { display: flex; }
  .nav__drawer .nav__link {
    font-size: var(--text-sm);
    padding: var(--space-2) 0;
    border-bottom: 1px solid var(--border-subtle);
  }

  /* Hero — stacked */
  .hero__body {
    grid-template-columns: 1fr;
    padding: 0 var(--page-padding);
  }
  .hero__left {
    padding: var(--space-10) 0 var(--space-8);
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  .hero__right {
    padding: var(--space-8) 0 var(--space-10);
  }

  /* Jony Ive directive: 2x2 vitals grid on tablet, full-width on phone */
  .hero__vitals-grid { grid-template-columns: 1fr 1fr; }

  .vital__value { font-size: 36px; }

  /* Ticker — narrower spacing */
  .ticker__item { padding: 0 var(--space-5); font-size: 10px; }

  /* Experiment — single column */
  .experiment {
    grid-template-columns: 1fr;
    padding: var(--space-12) var(--page-padding);
  }
  .experiment__sticky { position: static; }

  .progress-numbers { grid-template-columns: 1fr 1fr; gap: var(--space-4); }
  .prog-stat__value { font-size: 30px; }

  /* Sources — fewer columns */
  .sources-grid { grid-template-columns: repeat(3, 1fr); }

  /* Platform — 2 col */
  .platform-grid { grid-template-columns: 1fr 1fr; }

  /* Writing */
  .writing-grid { grid-template-columns: 1fr; }

  /* Footer — stacked */
  .footer {
    flex-direction: column;
    gap: var(--space-5);
    text-align: center;
    padding: var(--space-8) var(--page-padding);
  }
  .footer__links { justify-content: center; }

  /* Character page */
  .character-card { grid-template-columns: 1fr; }
  .cc-left { border-right: none; border-bottom: 1px solid var(--border); }
  .pillars-grid { grid-template-columns: 1fr 1fr; }
  .page-header { padding: calc(var(--nav-height) + var(--space-10)) var(--page-padding) var(--space-8); }

  /* Platform page */
  .arch-layer { grid-template-columns: 1fr; }
  .arch-layer__label { border-right: none; border-bottom: 1px solid var(--border); }
  .stack-grid { grid-template-columns: 1fr; }
  .ai-section { grid-template-columns: 1fr; }
  .review-grid { grid-template-columns: 1fr 1fr; }

  /* Journal */
  .journal-post { grid-template-columns: 1fr; gap: var(--space-2); }
  .journal-post__date { padding-top: 0; }

  /* Post */
  .prose p { font-size: 17px; }
  .data-callout__grid { grid-template-columns: 1fr 1fr; }

  .hide-mobile { display: none; }
  .show-mobile { display: block; }
}

/* ── sm: 480px (large phone) ─────────────────────────────── */
@media (max-width: 480px) {
  :root { --page-padding: 20px; }

  /* John Maeda directive: ONE vital hero on small phone */
  .hero__vitals-grid { grid-template-columns: 1fr; }

  /* Show only the most important vital on small screens */
  .hero__vitals-grid .vital:nth-child(2),
  .hero__vitals-grid .vital:nth-child(3),
  .hero__vitals-grid .vital:nth-child(4) {
    display: none;
  }
  .hero__vitals-see-all {
    display: block;
    font-size: var(--text-xs);
    color: var(--accent);
    letter-spacing: var(--ls-tag);
    text-transform: uppercase;
    margin-top: var(--space-3);
    cursor: pointer;
    text-decoration: none;
  }
  /* When expanded, show all */
  .hero__vitals-grid.expanded .vital { display: block; }

  .hero__name { font-size: clamp(60px, 18vw, 88px); }

  .hero__ctas { flex-direction: column; align-items: flex-start; gap: var(--space-3); }
  .hero__ctas .btn { width: 100%; text-align: center; }

  .progress-numbers { grid-template-columns: 1fr 1fr; gap: var(--space-3); }
  .prog-stat__value { font-size: 26px; }

  .sources-grid { grid-template-columns: 1fr 1fr; }
  .platform-grid { grid-template-columns: 1fr; }

  /* Character */
  .pillars-grid { grid-template-columns: 1fr; }
  .cc-stats { grid-template-columns: 1fr 1fr; }

  /* Platform */
  .review-grid { grid-template-columns: 1fr; }
  .page-header { grid-template-columns: 1fr; }
  .page-header__meta { grid-template-columns: 1fr 1fr; }
}

/* ── xs: 320px (small phone) ─────────────────────────────── */
@media (max-width: 360px) {
  :root { --page-padding: 16px; }
  .hero__name { font-size: 52px; }
  .ticker__item { padding: 0 var(--space-4); }
}