/* Once Upon a Concept: a brighter, playful skin on the shared Storybook styles. */

body.explain {
  --bg: #f3f7fc;
  --paper: #fffdf8;
  --paper-edge: #dfe7f1;
  --ink: #1f2a3a;
  --ink-soft: #46546a;
  --muted: #7a8698;
  --line: #d9e2ee;
  --accent: #2f6fd0;
  --accent-ink: #ffffff;
  --accent-soft: #dce8fb;
  --sun: #ffc93c;
  --good: #2e9d6a;
  --bad: #e0574f;
  --tool-bg: #eef5ff;
  --tool-line: #c8daf5;
  --display: "Fredoka", "Nunito", system-ui, sans-serif;
  --serif: "Nunito", system-ui, sans-serif;
  --sans: "Nunito", system-ui, sans-serif;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) body.explain {
    --bg: #121823; --paper: #1b2330; --paper-edge: #2a3546; --ink: #eef3fb; --ink-soft: #c3cede; --muted: #8b98ab;
    --line: #2f3b4e; --accent: #6ea4ff; --accent-ink: #0d1420; --accent-soft: #233552; --sun: #ffd45e;
    --good: #4cc08a; --bad: #ff7a72; --tool-bg: #1d2a3d; --tool-line: #2f4462;
  }
}
:root[data-theme="dark"] body.explain {
  --bg: #121823; --paper: #1b2330; --paper-edge: #2a3546; --ink: #eef3fb; --ink-soft: #c3cede; --muted: #8b98ab;
  --line: #2f3b4e; --accent: #6ea4ff; --accent-ink: #0d1420; --accent-soft: #233552; --sun: #ffd45e;
  --good: #4cc08a; --bad: #ff7a72; --tool-bg: #1d2a3d; --tool-line: #2f4462;
}

.explain h1, .explain h2, .explain h3 { font-weight: 600; letter-spacing: 0; }
.explain .btn { border-radius: 14px; }

/* Home */
.ex-hero-art { border-radius: 24px; overflow: hidden; box-shadow: var(--shadow); aspect-ratio: 800 / 420; }
.ex-hero-art svg { width: 100%; height: 100%; display: block; }
@media (max-width: 860px) { .ex-hero-art { display: none; } }

/* Form */
.explain #topic { font-size: 1.15rem; }
.explain .examples { margin-top: .6rem; }
.guides { display: grid; grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); gap: .6rem; }
.guide {
  border: 1px solid var(--line); background: var(--paper); border-radius: 14px; padding: 0; overflow: hidden; cursor: pointer; font: inherit; color: var(--ink);
}
.guide .gart { aspect-ratio: 4 / 3; overflow: hidden; }
.guide .gart svg { width: 100%; height: 100%; display: block; }
.guide span { display: block; padding: .4rem; font: 600 .85rem var(--sans); text-align: center; }
.guide[aria-pressed="true"] { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent); }
details.more { border: 1px dashed var(--line); border-radius: 14px; padding: .8rem 1rem; }
details.more summary { cursor: pointer; font-weight: 700; }
details.more[open] summary { margin-bottom: .8rem; }
details.more textarea { margin-bottom: 1rem; }

/* Writing screen */
.writing-diagram { max-width: 520px; margin: 0 auto; }
.writing-diagram svg { width: 100%; height: auto; }

/* Pages */
.book-stage { perspective: 1600px; }
.ex-page { min-height: 0; border-radius: 22px; }
@keyframes turn { from { opacity: 0; transform: rotateY(-16deg) translateX(40px); transform-origin: left center; } to { opacity: 1; transform: none; } }
.ex-page { animation: turn .55s cubic-bezier(.2, .7, .2, 1); }
.ex-page .kart { aspect-ratio: 800 / 420; overflow: hidden; }
.ex-page .kart svg { width: 100%; height: 100%; display: block; }
.ex-text { padding: clamp(1.25rem, 3.5vw, 2rem) clamp(1.25rem, 6vw, 3.5rem) .5rem; text-align: center; }
.ex-text p { font: 500 clamp(1.35rem, 3.2vw, 1.95rem)/1.42 var(--display); margin: 0; text-wrap: balance; }
.ex-text .w { display: inline-block; animation: wordin .45s ease both; }
@keyframes wordin { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

.teach { display: grid; grid-template-columns: 1fr; gap: 1rem; padding: 1.25rem clamp(1rem, 4vw, 2.25rem) 2rem; }
.panel { background: var(--tool-bg); border: 1px solid var(--tool-line); border-radius: 18px; padding: .9rem 1rem 1rem; position: relative; }
.panel-head { display: flex; justify-content: space-between; align-items: center; gap: .5rem; margin-bottom: .3rem; }
.panel-head strong { font: 600 1rem var(--display); }
.replay { border: 1px solid var(--line); background: var(--paper); color: var(--ink-soft); border-radius: 999px; padding: .2rem .65rem; font: 700 .75rem var(--sans); cursor: pointer; }
.dg { width: 100%; height: auto; display: block; overflow: visible; }

/* Flip card */
.flip { display: block; width: 100%; perspective: 1200px; border: 0; background: none; padding: 0; cursor: pointer; font: inherit; color: inherit; text-align: left; }
.flip-inner { display: block; position: relative; width: 100%; min-height: 150px; transform-style: preserve-3d; }
.flip[aria-pressed="true"] .flip-inner { transform: rotateY(180deg); animation: flipin .7s cubic-bezier(.3, 1.3, .5, 1); }
.flip[data-touched][aria-pressed="false"] .flip-inner { animation: flipout .7s cubic-bezier(.3, 1.3, .5, 1); }
@keyframes flipin { from { transform: rotateY(0); } to { transform: rotateY(180deg); } }
@keyframes flipout { from { transform: rotateY(180deg); } to { transform: rotateY(0); } }
.face {
  position: absolute; inset: 0; backface-visibility: hidden; -webkit-backface-visibility: hidden; border-radius: 18px;
  padding: 1.1rem 1.2rem; display: flex; flex-direction: column; justify-content: center; gap: .35rem;
}
.face small { font: 800 .7rem var(--sans); letter-spacing: .14em; text-transform: uppercase; opacity: .8; }
.face strong { font: 600 1.5rem/1.2 var(--display); }
.face.front { background: var(--sun); color: #3b2a00; box-shadow: inset 0 -4px 0 rgba(0,0,0,.08); }
.face.front em { font-style: normal; font-weight: 700; font-size: .85rem; opacity: .75; margin-top: .4rem; }
.face.back { background: var(--accent); color: var(--accent-ink); transform: rotateY(180deg); }
.face.back span { font-size: .98rem; line-height: 1.45; }
.flip:not([aria-pressed="true"]) .face.front { animation: nudge 3.5s ease-in-out 1.5s infinite; }
@keyframes nudge { 0%, 88%, 100% { transform: rotate(0); } 92% { transform: rotate(-1.5deg); } 96% { transform: rotate(1.5deg); } }

/* Diagram colors */
.dg .dg-box { fill: var(--paper); stroke: var(--line); stroke-width: 2; }
.dg .dg-hl { fill: var(--accent-soft); stroke: var(--accent); stroke-width: 3; }
.dg .dg-bad { fill: color-mix(in srgb, var(--bad) 14%, var(--paper)); stroke: var(--bad); stroke-width: 3; }
.dg .dg-label { fill: var(--ink); font-family: var(--sans); font-weight: 700; }
.dg .dg-onfill { fill: var(--ink); }
.dg .dg-arrow { fill: none; stroke: var(--muted); stroke-width: 2.5; stroke-linecap: round; stroke-linejoin: round; }
.dg .dg-track { stroke: var(--line); stroke-width: 4; stroke-dasharray: 2 8; stroke-linecap: round; }
.dg .dg-stop { fill: var(--line); }
.dg .dg-token rect { fill: var(--sun); stroke: #b8860b; stroke-width: 1.5; }
.dg .dg-token path { stroke: #b8860b; stroke-width: 1.5; }
.dg .dg-token-bad rect { fill: var(--bad); stroke: var(--bad); }
.dg .dg-token-bad path { stroke: #fff; }
.dg .dg-badge rect { fill: var(--bad); }
.dg .dg-badge-text { fill: #fff; font-family: var(--sans); font-weight: 800; }
.dg .dg-loop { fill: none; stroke: var(--accent); stroke-width: 3; stroke-dasharray: 10 8; opacity: .55; animation: march 1.2s linear infinite; }
@keyframes march { to { stroke-dashoffset: -18; } }
.dg .dg-center { font-size: 46px; fill: var(--accent); opacity: .35; }
.dg .dg-dot { fill: var(--sun); stroke: #b8860b; stroke-width: 1.5; }
.dg .dg-leak { fill: var(--bad); stroke: var(--bad); }
.dg .dg-axis { stroke: var(--line); stroke-width: 2; }
.dg .dg-bar { fill: color-mix(in srgb, var(--accent) 35%, var(--paper)); transform-box: fill-box; transform-origin: bottom; animation: grow .8s cubic-bezier(.2, .9, .3, 1.2) both; }
.dg .dg-bar.dg-hl { fill: var(--accent); stroke: none; }
.dg .dg-value { fill: var(--ink); font-weight: 800; font-family: var(--sans); }
.dg .dg-layer { fill: color-mix(in srgb, var(--accent) 30%, var(--paper)); }
.dg .dg-layer.dg-hl { fill: color-mix(in srgb, var(--accent) 60%, var(--paper)); stroke: var(--accent); stroke-width: 2; }
.dg .dg-block { fill: color-mix(in srgb, var(--sun) 55%, var(--paper)); stroke: #c99a1a; stroke-width: 1.5; }
.dg .dg-block.dg-hl { fill: var(--sun); stroke-width: 3; }
.dg .dg-in { animation: fadeup .5s ease both; }
.dg .dg-drop { animation: fadeup .5s ease both; }
.dg .dg-stack { animation: stack .7s cubic-bezier(.3, 1.4, .5, 1) both; }
.dg .dg-pulse { animation: pulse 1.6s ease-in-out infinite; transform-box: fill-box; transform-origin: center; }
.dg .dg-box.dg-hl { animation: hlpulse 2s ease-in-out infinite; }
@keyframes grow { from { transform: scaleY(0); } to { transform: scaleY(1); } }
@keyframes fadeup { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
@keyframes stack { from { opacity: 0; transform: translateY(-220px); } to { opacity: 1; transform: none; } }
@keyframes pulse { 0%, 100% { transform: scale(1); } 50% { transform: scale(1.08); } }
@keyframes hlpulse { 0%, 100% { stroke-width: 3; } 50% { stroke-width: 5; } }

/* End pages */
.ex-body { padding: clamp(1.5rem, 4vw, 2.75rem) clamp(1.25rem, 5vw, 3.25rem) 2.5rem; }
.ex-body h2 { font-size: clamp(1.6rem, 3.5vw, 2.2rem); margin-bottom: 1rem; }
.ideas { list-style: none; padding: 0; margin: 0 0 1.5rem; display: grid; gap: .7rem; counter-reset: idea; }
.ideas li {
  counter-increment: idea; display: flex; gap: .9rem; align-items: flex-start; background: var(--tool-bg); border: 1px solid var(--tool-line);
  border-radius: 16px; padding: .9rem 1rem; font-size: 1.08rem; animation: pop .5s cubic-bezier(.3, 1.5, .5, 1) both;
}
.ideas li::before {
  content: counter(idea); flex: none; width: 2rem; height: 2rem; border-radius: 50%; background: var(--accent); color: var(--accent-ink);
  display: grid; place-items: center; font: 600 1rem var(--display);
}
@keyframes pop { from { opacity: 0; transform: scale(.85) translateY(10px); } to { opacity: 1; transform: none; } }
.stretch { background: var(--bg); border: 1px dashed var(--line); border-radius: 14px; padding: 1rem 1.1rem; color: var(--ink-soft); }
.stretch strong { color: var(--ink); }

.quiz-q { border: 1px solid var(--line); border-radius: 18px; padding: 1rem 1.1rem 1.1rem; margin-bottom: 1rem; background: var(--paper); position: relative; }
.quiz-q h3 { font-size: 1.15rem; margin-bottom: .7rem; }
.quiz-opts { display: grid; gap: .5rem; }
.opt {
  text-align: left; border: 2px solid var(--line); background: var(--bg); color: var(--ink); border-radius: 12px; padding: .65rem .9rem;
  font: 700 1rem var(--sans); cursor: pointer;
}
.opt:hover:not(:disabled) { border-color: var(--accent); }
.opt.right { border-color: var(--good); background: color-mix(in srgb, var(--good) 15%, var(--paper)); }
.opt.wrong { border-color: var(--bad); background: color-mix(in srgb, var(--bad) 12%, var(--paper)); animation: shake .4s; }
.opt:disabled { cursor: default; }
@keyframes shake { 25% { transform: translateX(-6px); } 50% { transform: translateX(6px); } 75% { transform: translateX(-3px); } }
.quiz-exp { margin: .7rem 0 0; color: var(--ink-soft); }
.score { font: 600 1.2rem var(--display); text-align: center; margin-top: 1rem; }
.confetti { position: absolute; left: 50%; top: 40%; width: 9px; height: 9px; border-radius: 2px; pointer-events: none; animation: burst 1.1s ease-out forwards; }
@keyframes burst { from { transform: translate(0, 0) rotate(0); opacity: 1; } to { transform: translate(var(--dx), var(--dy)) rotate(540deg); opacity: 0; } }

.gloss { display: grid; gap: .6rem; margin: 0 0 1.75rem; }
.gloss div { border-bottom: 1px solid var(--line); padding-bottom: .55rem; }
.gloss dt { font: 600 1.05rem var(--display); }
.gloss dd { margin: .15rem 0 0; color: var(--ink-soft); }
.facts { background: color-mix(in srgb, var(--sun) 18%, var(--paper)); border: 1px solid color-mix(in srgb, var(--sun) 60%, var(--line)); border-radius: 16px; padding: 1rem 1.2rem; }
.facts h3 { font-size: 1.05rem; margin-bottom: .4rem; }
.facts ul { margin: 0; padding-left: 1.2rem; }

.ex-end { text-align: center; padding: 1.5rem 1rem 2.5rem; }
.ex-end h2 { font-size: clamp(2.4rem, 7vw, 3.6rem); color: var(--accent); margin: .25rem 0; }
.ex-end .actions { display: flex; gap: .6rem; justify-content: center; flex-wrap: wrap; margin-top: 1.2rem; }

@media (prefers-reduced-motion: reduce) {
  .ex-page, .ex-text .w, .ideas li, .dg *, .flip-inner, .face.front { animation: none !important; transition: none !important; }
}
@media print {
  .flip-inner { transform: none !important; min-height: 0; }
  .face { position: static; margin-bottom: .5rem; }
  .face.back { transform: none; }
  .replay { display: none; }
}