/* ============================================================
   Learn Something New — Animations
   Soft fades, gentle lifts, breathing pills, stroke draws.
   All respect prefers-reduced-motion.
   ============================================================ */

:root {
  --ease-out:  cubic-bezier(0.22, 0.61, 0.36, 1);
  --ease-in:   cubic-bezier(0.55, 0.06, 0.68, 0.19);
  --ease-soft: cubic-bezier(0.4, 0.0, 0.2, 1);
  --ease-quill: cubic-bezier(0.2, 0.7, 0.2, 1);

  --dur-fast:  140ms;
  --dur-base:  240ms;
  --dur-rise:  400ms;
  --dur-slow:  640ms;
}

/* ---------- Mount fade/rise for view transitions ---------- */

.mount-enter {
  opacity: 0;
  transform: translateY(12px);
}

.mount-enter-active {
  opacity: 1;
  transform: translateY(0);
  transition:
    opacity var(--dur-rise) var(--ease-out),
    transform var(--dur-rise) var(--ease-out);
}

.mount-exit {
  opacity: 1;
  transform: translateY(0);
}

.mount-exit-active {
  opacity: 0;
  transform: translateY(0);
  transition: opacity 200ms var(--ease-in);
}

/* ---------- Page enter (a richer settle: opacity + lift + blur) ---------- */

@keyframes page-enter-kf {
  0% {
    opacity: 0;
    transform: translateY(14px);
    filter: blur(4px);
  }
  60% {
    filter: blur(0.6px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
    filter: blur(0);
  }
}

.page-enter {
  animation: page-enter-kf 600ms var(--ease-quill) both;
}

/* ---------- Depth-change transitions (reader level advance/retreat) ---------- */
/* #app gets depth-exit-* during fade-out, then depth-enter-* during fade-in.
   "deeper" = descending; "back" = retreating. Ink-bleed via blur + slight scale. */

@keyframes depth-deeper-out-kf {
  0%   { opacity: 1; transform: translateY(0) scale(1);      filter: blur(0); }
  100% { opacity: 0; transform: translateY(-22px) scale(0.985); filter: blur(5px); }
}
@keyframes depth-deeper-in-kf {
  0%   { opacity: 0; transform: translateY(26px) scale(1.012); filter: blur(6px); }
  55%  { filter: blur(1px); }
  100% { opacity: 1; transform: translateY(0) scale(1);        filter: blur(0); }
}
@keyframes depth-back-out-kf {
  0%   { opacity: 1; transform: translateY(0) scale(1);       filter: blur(0); }
  100% { opacity: 0; transform: translateY(20px) scale(1.01); filter: blur(5px); }
}
@keyframes depth-back-in-kf {
  0%   { opacity: 0; transform: translateY(-22px) scale(0.99); filter: blur(6px); }
  55%  { filter: blur(1px); }
  100% { opacity: 1; transform: translateY(0) scale(1);        filter: blur(0); }
}

.depth-exit-deeper { animation: depth-deeper-out-kf 240ms var(--ease-in) both; }
.depth-exit-back   { animation: depth-back-out-kf   240ms var(--ease-in) both; }
.depth-enter-deeper { animation: depth-deeper-in-kf 520ms var(--ease-quill) both; }
.depth-enter-back   { animation: depth-back-in-kf   460ms var(--ease-quill) both; }

/* ---------- Staggered entrance for grid items ---------- */

@keyframes rise-in {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: translateY(0); }
}

.rise {
  animation: rise-in var(--dur-rise) var(--ease-out) both;
}

.stagger > * {
  animation: rise-in var(--dur-rise) var(--ease-out) both;
}
.stagger > *:nth-child(1)  { animation-delay: 40ms; }
.stagger > *:nth-child(2)  { animation-delay: 80ms; }
.stagger > *:nth-child(3)  { animation-delay: 120ms; }
.stagger > *:nth-child(4)  { animation-delay: 160ms; }
.stagger > *:nth-child(5)  { animation-delay: 200ms; }
.stagger > *:nth-child(6)  { animation-delay: 240ms; }
.stagger > *:nth-child(7)  { animation-delay: 280ms; }
.stagger > *:nth-child(8)  { animation-delay: 320ms; }
.stagger > *:nth-child(9)  { animation-delay: 360ms; }
.stagger > *:nth-child(10) { animation-delay: 400ms; }
.stagger > *:nth-child(11) { animation-delay: 440ms; }
.stagger > *:nth-child(12) { animation-delay: 480ms; }

/* ---------- Reveal on scroll (IntersectionObserver hook) ---------- */

.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition:
    opacity 700ms var(--ease-quill),
    transform 700ms var(--ease-quill);
  will-change: opacity, transform;
}
.reveal.is-in {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Prose waterfall reveal (per-block in reader) ---------- */

.prose-reveal {
  /* slightly smaller offset than card .reveal for a calmer cadence */
  transform: translateY(14px);
}
.prose-reveal.is-in { transform: translateY(0); }

/* cap the cascade so deep prose doesn't lag — repeat every 5 */
.prose-reveal:nth-child(5n + 1) { transition-delay: 0ms; }
.prose-reveal:nth-child(5n + 2) { transition-delay: 60ms; }
.prose-reveal:nth-child(5n + 3) { transition-delay: 120ms; }
.prose-reveal:nth-child(5n + 4) { transition-delay: 180ms; }
.prose-reveal:nth-child(5n + 5) { transition-delay: 240ms; }

/* The drop-cap lives on the first prose <p>, now inside .prose-reveal.
   Keep the drop-cap selector working through the wrapper (see C7). */

/* When inside a staggered grid, give each card a touch more delay */
.stagger > .reveal:nth-child(2)  { transition-delay: 40ms; }
.stagger > .reveal:nth-child(3)  { transition-delay: 80ms; }
.stagger > .reveal:nth-child(4)  { transition-delay: 120ms; }
.stagger > .reveal:nth-child(5)  { transition-delay: 160ms; }
.stagger > .reveal:nth-child(6)  { transition-delay: 200ms; }
.stagger > .reveal:nth-child(7)  { transition-delay: 240ms; }
.stagger > .reveal:nth-child(8)  { transition-delay: 280ms; }
.stagger > .reveal:nth-child(9)  { transition-delay: 320ms; }

/* ---------- Stroke-draw on SVG paths ----------
   SVGs author paths with stroke-dasharray + a large stroke-dashoffset
   set inline. When the SVG (.draw-on-view) becomes visible, the
   IntersectionObserver adds .is-drawn — the paths are then animated
   toward stroke-dashoffset: 0.
   We can't easily transition inline-attribute dashoffset, but we can
   re-declare via CSS using path { transition }.
   ---------------------------------------------- */

.draw-on-view img,
.draw-on-view svg {
  /* Initial state: nudged + transparent */
  opacity: 0;
  transform: scale(0.985);
  transition:
    opacity 900ms var(--ease-quill),
    transform 1200ms var(--ease-quill);
}
.draw-on-view.is-drawn img,
.draw-on-view.is-in img,
.draw-on-view.is-drawn svg,
.draw-on-view.is-in svg {
  opacity: 1;
  transform: scale(1);
}

/* For inlined SVGs, also animate the stroke dasharray on .draw-paths */
.draw-on-view svg .draw-paths,
.draw-on-view svg .draw-paths > * {
  transition: stroke-dashoffset 1300ms var(--ease-out);
}
.draw-on-view.is-drawn svg .draw-paths,
.draw-on-view.is-drawn svg .draw-paths > *,
.draw-on-view.is-in svg .draw-paths,
.draw-on-view.is-in svg .draw-paths > * {
  stroke-dashoffset: 0 !important;
}

/* ---------- Breathing pulse for Continue button ---------- */

@keyframes breathe {
  0%, 100% {
    opacity: 1;
    box-shadow:
      0 1px 2px rgba(26, 20, 16, 0.15),
      0 14px 28px -14px rgba(26, 20, 16, 0.45),
      0 0 0 0 rgba(184, 146, 58, 0.0);
  }
  50% {
    opacity: 0.97;
    box-shadow:
      0 1px 2px rgba(26, 20, 16, 0.15),
      0 18px 32px -14px rgba(26, 20, 16, 0.45),
      0 0 0 8px rgba(184, 146, 58, 0.06);
  }
}

.breathe {
  animation: breathe 3.4s var(--ease-soft) infinite;
}

/* ---------- Ornament drift ---------- */

@keyframes ornament-glow {
  0%, 100% { opacity: 0.65; transform: scale(1); }
  50%      { opacity: 1;    transform: scale(1.04); }
}

.ornament-glow {
  animation: ornament-glow 6s var(--ease-soft) infinite;
}

/* ---------- Hover transitions ---------- */

.tx-lift {
  transition:
    transform var(--dur-base) var(--ease-out),
    box-shadow var(--dur-base) var(--ease-out),
    border-color var(--dur-base) var(--ease-out);
}

.tx-fade {
  transition:
    opacity var(--dur-base) var(--ease-out),
    color var(--dur-base) var(--ease-out),
    background-color var(--dur-base) var(--ease-out);
}

/* ---------- Progress thread fill + living dot halo ---------- */

@keyframes thread-fill-kf {
  from { transform: scaleX(0); }
  to   { transform: scaleX(1); }
}

@keyframes dot-halo-kf {
  0%, 100% { box-shadow: 0 0 0 0   rgba(184, 85, 46, 0.0); }
  50%      { box-shadow: 0 0 0 6px rgba(184, 85, 46, 0.14); }
}

@keyframes dot-done {
  from { transform: scale(0.7); }
  to   { transform: scale(1); }
}
.rail-dot.is-done { animation: dot-done 280ms var(--ease-out); }

/* ---------- Glyph float (corner glyphs on cards / heads) ---------- */

@keyframes glyph-float {
  0%, 100% { transform: translateY(0) rotate(0); }
  50%      { transform: translateY(-4px) rotate(-2deg); }
}

/* Float the corner glyphs only on hover-capable devices. On phones, 15+ of
   these looping at once (plus the ambient canvas) is needless battery/jank;
   they stay perfectly visible, just static. */
@media (hover: hover) and (pointer: fine) {
  .cat-card .cat-glyph,
  .topic-card .topic-glyph {
    animation: glyph-float 4.6s var(--ease-soft) infinite;
  }
}

/* ---------- Hero glyph slow rotation (orrery) ---------- */

@keyframes slow-rotate {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

/* Match both the <img> and the inline <svg> it becomes after hydration,
   otherwise the rotation silently stops once the SVG is inlined. */
.hero-orrery img,
.hero-orrery svg {
  animation: slow-rotate 90s linear infinite;
  transform-origin: 50% 50%;
}

/* ---------- Hero title shimmer (one-shot gold sweep) ---------- */

@keyframes title-shimmer {
  0%   { background-position: -120% 0; }
  100% { background-position: 220% 0; }
}

.shimmer-once {
  background-image: linear-gradient(
    100deg,
    currentColor 0%,
    currentColor 40%,
    rgba(184, 146, 58, 0.85) 50%,
    currentColor 60%,
    currentColor 100%
  );
  background-size: 220% 100%;
  background-position: -120% 0;
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
  animation: title-shimmer 1.6s var(--ease-soft) 200ms 1 both;
}
.shimmer-once .italic {
  /* preserve italic accent color through the gradient */
  -webkit-text-fill-color: var(--accent-deep);
  color: var(--accent-deep);
}

/* ---------- Pull-quote entrance ---------- */

@keyframes pullquote-in {
  0%   { opacity: 0; transform: translateX(-10px); }
  100% { opacity: 1; transform: translateX(0); }
}

.pullquote {
  animation: pullquote-in 700ms var(--ease-quill) 220ms both;
}

/* ---------- Level title settle (reader subhead eases in italic) ---------- */

@keyframes level-title-settle {
  0%   { opacity: 0; transform: translateY(6px); letter-spacing: 0.02em; }
  100% { opacity: 1; transform: translateY(0);   letter-spacing: -0.012em; }
}
.reader-level-title {
  animation: level-title-settle 560ms var(--ease-quill) 120ms both;
}

/* ---------- Drop-cap reveal ---------- */

@keyframes dropcap-in {
  0%   { opacity: 0; transform: scale(0.7); }
  100% { opacity: 1; transform: scale(1); }
}

.reader-body .prose-reveal:first-of-type p:first-of-type::first-letter,
.reader-body > p:first-of-type::first-letter {
  display: inline-block;
  animation: dropcap-in 500ms var(--ease-quill) 360ms both;
}

/* ---------- Drop / finis ornament fade ---------- */

@keyframes drop-orn-in {
  0%   { opacity: 0; transform: translateY(-6px); }
  100% { opacity: 0.55; transform: translateY(0); }
}
.drop-ornament,
.finis-ornament {
  animation: drop-orn-in 700ms var(--ease-quill) 200ms both;
}

/* ---------- Completion celebratory rings ---------- */

@keyframes ring-pulse {
  0%   { transform: scale(0.4); opacity: 0; }
  20%  { opacity: 0.6; }
  100% { transform: scale(2.4); opacity: 0; }
}

.complete-rings .ring {
  position: absolute;
  left: 50%; top: 50%;
  width: 120px; height: 120px;
  margin: -60px 0 0 -60px;
  border-radius: 50%;
  border: 1px solid var(--gold);
  opacity: 0;
  pointer-events: none;
}
.complete-rings .ring.r1 { animation: ring-pulse 3.4s var(--ease-soft) infinite; }
.complete-rings .ring.r2 { animation: ring-pulse 3.4s var(--ease-soft) infinite 0.6s; }
.complete-rings .ring.r3 { animation: ring-pulse 3.4s var(--ease-soft) infinite 1.2s; }
.complete-rings .ring.r4 { animation: ring-pulse 3.4s var(--ease-soft) infinite 1.8s; }

/* ---------- Page transition overlay sweep ---------- */

@keyframes page-wipe {
  0%   { transform: translateX(-100%); opacity: 0; }
  30%  { opacity: 0.18; }
  100% { transform: translateX(100%); opacity: 0; }
}

#page-transition.is-active::after {
  animation: page-wipe 700ms var(--ease-quill);
}

/* ---------- Completion glyph gentle float/glow ---------- */

@keyframes complete-glyph-kf {
  0%, 100% { transform: translateY(0) scale(1); text-shadow: 0 0 0 rgba(184,146,58,0); }
  50%      { transform: translateY(-5px) scale(1.03); text-shadow: 0 0 22px rgba(184,146,58,0.35); }
}
.complete-rings .complete-ornament {
  animation: complete-glyph-kf 5s var(--ease-soft) infinite;
}

/* ---------- Surprise tile dice glyph life ---------- */

@keyframes dice-tumble-kf {
  0%, 100% { transform: rotate(0deg) scale(1); }
  25%      { transform: rotate(8deg) scale(1.04); }
  50%      { transform: rotate(-6deg) scale(1.02); }
  75%      { transform: rotate(4deg) scale(1.05); }
}
@media (hover: hover) and (pointer: fine) {
  .cat-card.surprise .cat-glyph {
    animation: dice-tumble-kf 6s var(--ease-soft) infinite;
  }
  .cat-card.surprise:hover .cat-glyph {
    animation-duration: 2.4s;
  }
}

/* ---------- Reduced motion: kill all transforms ---------- */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 80ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 80ms !important;
    scroll-behavior: auto !important;
  }

  .mount-enter,
  .mount-enter-active,
  .mount-exit,
  .mount-exit-active,
  .rise,
  .stagger > *,
  .reveal,
  .prose-reveal,
  .reader-level-title,
  .depth-enter-deeper,
  .depth-enter-back,
  .depth-exit-deeper,
  .depth-exit-back,
  .page-enter,
  .pullquote,
  .draw-on-view img,
  .draw-on-view svg {
    transform: none !important;
    filter: none !important;
    opacity: 1 !important;
  }

  .breathe,
  .ornament-glow,
  .hero-orrery img,
  .hero-orrery svg,
  .complete-rings .ring,
  .thread-fill,
  .rail-dot.is-current .rail-dot-inner,
  .drop-ornament,
  .complete-rings .complete-ornament,
  .cat-card.surprise .cat-glyph,
  .cat-card .cat-glyph,
  .topic-card .topic-glyph,
  .reader-level-title,
  .shimmer-once {
    animation: none !important;
    opacity: 1 !important;
  }

  .depth-enter-deeper, .depth-enter-back,
  .depth-exit-deeper, .depth-exit-back {
    animation: none !important;
    transform: none !important;
    filter: none !important;
    opacity: 1 !important;
  }
  .thread-fill {
    /* keep the static width (no scaleX animation) */
    transform: none !important;
    animation: none !important;
  }
  .scroll-hairline-fill {
    transition: none !important;
  }
  .card-tilt:hover {
    transform: none !important;   /* no tilt */
  }
  .card-tilt {
    background-image: none !important; /* no pointer bloom */
  }

  .shimmer-once {
    -webkit-text-fill-color: currentColor !important;
    color: var(--ink) !important;
    background: none !important;
  }

  .tx-lift:hover {
    transform: none !important;
  }

  #page-transition.is-active::after {
    animation: none !important;
  }
}