@layer reset, tokens, base, components, pages, utilities;

@layer reset {
  *, *::before, *::after { box-sizing: border-box; margin: 0; }
  html { -webkit-text-size-adjust: 100%; }
  body { min-height: 100dvh; }
  img, svg { display: block; max-width: 100%; }
  button, input, select, textarea { font: inherit; color: inherit; }
  button { background: none; border: 0; padding: 0; cursor: pointer; }
  a { color: inherit; }
  table { border-collapse: collapse; }
  h1, h2, h3, h4 { font-weight: 800; letter-spacing: var(--tracking-tight); line-height: var(--lh-tight); text-wrap: balance; }
  p { text-wrap: pretty; }
  :where([hidden]) { display: none !important; }
}

@layer base {
  html { scroll-behavior: smooth; scroll-padding-top: calc(var(--topbar-h) + 72px); }
  body { font-family: var(--font); font-size: var(--fs-base); line-height: var(--lh); color: var(--text); background: var(--bg); font-feature-settings: 'ss01'; transition: background-color var(--t-slow), color var(--t-slow); }
  :focus-visible { outline: none; box-shadow: var(--focus); border-radius: var(--r-sm); }
  ::selection { background: color-mix(in oklab, var(--glas) 45%, transparent); }
  a.link, .link { color: var(--link); text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; font-weight: 600; }
  .link:hover { text-decoration-thickness: 2px; }
  .muted { color: var(--text-3); }
  .num, .tnum { font-variant-numeric: tabular-nums; }
  .sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
  .caps { font-size: var(--fs-xs); font-weight: 700; letter-spacing: var(--tracking-caps); text-transform: uppercase; color: var(--text-3); }
  code { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.9em; background: var(--surface-2); padding: 1px 5px; border-radius: 4px; }

  /* ---- view transitions (progressive) ---- */
  @view-transition { navigation: auto; }
  ::view-transition-old(root), ::view-transition-new(root) { animation-duration: 220ms; }
  ::view-transition-old(page) { animation: 160ms var(--ease) both vt-out; }
  ::view-transition-new(page) { animation: 240ms var(--ease) both vt-in; }
  @keyframes vt-in { from { opacity: 0; transform: translateY(8px); } }
  @keyframes vt-out { to { opacity: 0; } }
  main.page { view-transition-name: page; }

  /* ---- reveal on scroll (with scroll-driven fallback) ---- */
  .rv { opacity: 0; transform: translateY(18px); transition: opacity 600ms var(--ease), transform 600ms var(--ease); transition-delay: var(--d, 0ms); }
  .rv.in { opacity: 1; transform: none; }
  .no-anim .rv { opacity: 1; transform: none; transition: none; }

  @media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    *, *::before, *::after { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; }
    .rv { opacity: 1; transform: none; }
    ::view-transition-group(*), ::view-transition-old(*), ::view-transition-new(*) { animation: none !important; }
  }
}

@layer utilities {
  .stack > * + * { margin-top: var(--gap, var(--s-4)); }
  .row { display: flex; align-items: center; gap: var(--gap, var(--s-3)); flex-wrap: wrap; }
  .between { justify-content: space-between; }
  .grow { flex: 1; min-width: 0; }
  .right { text-align: right; }
  .center { text-align: center; }
  .mt-2 { margin-top: var(--s-2); } .mt-3 { margin-top: var(--s-3); } .mt-4 { margin-top: var(--s-4); } .mt-5 { margin-top: var(--s-5); } .mt-6 { margin-top: var(--s-6); }
  .mb-3 { margin-bottom: var(--s-3); } .mb-4 { margin-bottom: var(--s-4); }
  .small { font-size: var(--fs-sm); }
  .xs { font-size: var(--fs-xs); }
  .strong { font-weight: 700; }
  .nowrap { white-space: nowrap; }
  .break { overflow-wrap: anywhere; }
  .grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 280px), 1fr)); gap: var(--s-4); }
  .grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 220px), 1fr)); gap: var(--s-4); }
  .hide-print { }
  @media print {
    .no-print, .hide-print, db-sidebar, .topbar, .toast-region, .chapter-nav, .btn { display: none !important; }
    body { background: #fff; color: #000; font-size: 11pt; }
    .card { box-shadow: none; border: 1px solid #ccc; break-inside: avoid; }
    a { text-decoration: none; }
    .lvl { margin-top: 18pt; }
    .app-grid { display: block; }
    .wrap { padding: 0; max-width: none; }
    details { open: true; }
    details > summary { list-style: none; }
    .ab { grid-template-rows: 1fr !important; }
    .print-only { display: block !important; }
  }
  .print-only { display: none; }
}