/* =========================================================================
   SCAPE° app kit – the shared skeleton and components of every app
   (style guide: poster site, buttons, info buttons, Merke box, collapsible
   topics, stage with fullscreen button and first-hint badge, layout).
   Uses only variables from theme/theme.css. Identical in every app;
   app-specific layout goes into css/app.css.

   Phone layout is the base; html[data-view="desktop"] (set by js/view.js
   from the screen width or the header toggle) switches to the desktop
   arrangement: interactive left, controls right.
   ========================================================================= */

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--paper); color: var(--ink);
  font-family: var(--font); font-weight: var(--fw-regular); font-size: 17px; line-height: 1.45;
  overflow-x: hidden; -webkit-tap-highlight-color: transparent;
}
h1, h2, h3, p { margin: 0; }
b, strong { font-weight: var(--fw-medium); }
a { color: inherit; }
button, input, select { font: inherit; color: inherit; }
[hidden] { display: none !important; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }

:root { --gutter: clamp(16px, 4vw, 48px); --head-h: 76px; }

/* ---------- Header (sticky) ---------------------------------------------- */
.top {
  position: sticky; top: 0; z-index: 30;
  display: flex; flex-wrap: wrap; align-items: flex-end; justify-content: space-between; gap: 12px 20px;
  padding: 16px var(--gutter) 12px; background: var(--paper);
  border-bottom: var(--line-width) solid var(--line); --logo-size: 34px;
}
.top-right { display: flex; flex-wrap: wrap; align-items: center; justify-content: flex-end; gap: 6px; }
.nav { display: flex; flex-wrap: wrap; gap: 6px; }
.nav a, .nav button {
  display: inline-flex; align-items: center; min-height: 40px; padding: 6px 12px;
  border: var(--line-width) solid var(--line); border-radius: var(--radius); background: var(--paper);
  text-decoration: none; font-weight: var(--fw-medium); font-size: 13px; letter-spacing: .04em; text-transform: var(--caps);
  cursor: pointer;
}
.nav .num { font-weight: var(--fw-light); margin-right: 6px; }
.nav [aria-current="page"], .nav [aria-current="true"] { background: var(--active); color: var(--active-ink); }
.view-toggle {
  min-height: 40px; padding: 6px 10px; border: var(--line-width) solid var(--line); background: var(--paper);
  font-weight: var(--fw-medium); font-size: 11px; letter-spacing: .05em; text-transform: var(--caps); cursor: pointer; white-space: nowrap;
}
:root[data-view="mobile"] .top { position: static; }
:root[data-view="mobile"] .top-right:has(.nav) { width: 100%; justify-content: space-between; }
:root[data-view="mobile"] .nav { flex: 1 1 100%; order: 2; }
:root[data-view="mobile"] .nav a, :root[data-view="mobile"] .nav button { flex: 1 1 auto; justify-content: center; padding: 6px 8px; font-size: 12px; }
:root[data-view="mobile"] .view-toggle { margin-left: auto; }

/* ---------- Poster header (three CD layers) ------------------------------ */
.poster { position: relative; overflow: hidden; isolation: isolate; min-height: 280px; padding: 36px var(--gutter) 44px; }
.poster .f { position: absolute; z-index: -3; }
.poster .f1 { inset: 0; background: var(--f1); }
.poster .f2 { top: 0; right: 0; width: 30%; height: 58%; background: var(--f2); }
.poster .f3 { bottom: 0; right: 0; width: 30%; height: 42%; background: var(--f3); }
.poster .l2 { position: absolute; z-index: -2; right: calc(30% - 60px); top: calc(58% - 60px); width: 120px; height: 120px; color: var(--shape); }
.poster .l3 { position: absolute; z-index: -1; right: -12%; top: -40%; width: min(66vw, 700px); height: auto; color: var(--outline); fill: none; stroke: currentColor; stroke-width: 3; pointer-events: none; }
.poster .l3 * { vector-effect: non-scaling-stroke; }
.poster-text { position: relative; max-width: min(66%, 900px); }
.kicker { font-weight: var(--fw-medium); font-size: 13px; letter-spacing: .07em; text-transform: var(--caps); margin-bottom: 12px; }
.headline { font-weight: var(--fw-light); text-transform: var(--caps); font-size: clamp(42px, 8vw, 116px); line-height: .88; letter-spacing: -.005em; margin-bottom: 18px; overflow-wrap: anywhere; hyphens: manual; }
.lead { font-size: clamp(17px, 1.7vw, 20px); max-width: 40em; }
/* slim band: sub-pages, and single-page apps on the desktop */
.poster.small { min-height: 0; padding: 26px var(--gutter) 30px; }
.poster.small .headline { font-size: clamp(36px, 6vw, 84px); margin-bottom: 12px; }
.poster.small .l2 { width: 90px; height: 90px; right: calc(30% - 45px); top: calc(58% - 45px); }
:root[data-view="desktop"] .poster.small { padding: 20px var(--gutter) 22px; }
:root[data-view="desktop"] .poster.small .headline { font-size: clamp(38px, 4vw, 60px); margin-bottom: 10px; }
:root[data-view="desktop"] .poster.small .kicker { margin-bottom: 8px; }
:root[data-view="desktop"] .poster.small .lead { font-size: 17px; }
:root[data-view="desktop"] .poster.small .l3 { top: -60%; width: min(44vw, 540px); }
:root[data-view="mobile"] .poster, :root[data-view="mobile"] .poster.small { min-height: 0; padding: 26px var(--gutter) 96px; }
:root[data-view="mobile"] .poster-text { max-width: 100%; }
:root[data-view="mobile"] .poster .f2 { top: auto; bottom: 0; left: 0; right: auto; width: 58%; height: 70px; }
:root[data-view="mobile"] .poster .f3 { bottom: 0; right: 0; width: 42%; height: 70px; }
:root[data-view="mobile"] .poster .l2 { right: auto; left: calc(58% - 40px); top: auto; bottom: 28px; width: 80px; height: 80px; }
/* phone: only the top of the large outline shows, rising out of the colour band, so it never crosses the text */
:root[data-view="mobile"] .poster .l3 { width: 95vw; right: -25%; top: auto; bottom: 0; transform: translateY(70%); }

/* ---------- Page body ---------------------------------------------------- */
.page { padding: 20px var(--gutter) 40px; max-width: 1400px; margin: 0 auto; }
.section-label { font-weight: var(--fw-medium); font-size: 12px; letter-spacing: .1em; text-transform: var(--caps); margin: 18px 0 8px; }
.section-label:first-child { margin-top: 0; }
.h2-short { font-weight: var(--fw-light); text-transform: var(--caps); font-size: clamp(30px, 3.4vw, 46px); line-height: .92; margin: 0 0 12px; }
.h2-question { font-weight: var(--fw-medium); font-size: clamp(22px, 2.4vw, 30px); line-height: 1.15; margin: 0 0 12px; }
p.text { font-size: 16px; line-height: 1.55; max-width: 46em; margin: 0 0 12px; }

/* ---------- Lab: interactive + controls ----------------------------------
   Phone: pre (selection) → stage → post (controls, hint, tasks, Merke).
   Desktop: stage on the left, sized to the screen; pre + post on the right. */
.lab { display: grid; grid-template-columns: minmax(0, 1fr); grid-template-areas: "pre" "stage" "post"; gap: 12px 36px; align-items: start; }
.lab-pre { grid-area: pre; min-width: 0; }
.lab-stage { grid-area: stage; min-width: 0; }
.lab-post { grid-area: post; min-width: 0; }
:root[data-view="desktop"] .lab {
  grid-template-columns: minmax(0, 1fr) minmax(min(320px, 45%), 420px);
  grid-template-areas: "stage pre" "stage post";
  grid-template-rows: auto 1fr;
}
:root[data-view="desktop"] .lab-stage { position: sticky; top: calc(var(--head-h) + 12px); }
/* a square stage that fits the screen on the desktop */
.stage-frame.square { aspect-ratio: 1 / 1; }
:root[data-view="desktop"] .stage-frame.fit { width: min(100%, calc(100svh - var(--head-h) - var(--fit-offset, 230px))); min-width: min(360px, 100%); margin: 0 auto; }

/* ---------- Stage frame, fullscreen button, first-hint badge ------------- */
.stage-frame { position: relative; border: var(--line-width) solid var(--line); background: var(--stage-bg); }
.stage-frame > canvas { display: block; width: 100%; height: 100%; }
.fs-btn {
  position: absolute; right: 8px; bottom: 8px; z-index: 6; width: 40px; height: 40px; padding: 0;
  display: flex; align-items: center; justify-content: center;
  border: var(--line-width) solid var(--line); background: var(--paper); cursor: pointer;
}
.fs-btn svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 2; }
.fs-btn .exit { display: none; }
.stage-frame.is-full .fs-btn .enter, .stage-frame:fullscreen .fs-btn .enter { display: none; }
.stage-frame.is-full .fs-btn .exit, .stage-frame:fullscreen .fs-btn .exit { display: block; }
/* fallback where the Fullscreen API is missing (iPhone): fill the window */
.stage-frame.is-full { position: fixed; inset: 0; z-index: 1000; width: auto !important; height: auto !important; aspect-ratio: auto !important; border: 0; margin: 0 !important; }
.stage-frame:fullscreen { width: 100% !important; height: 100% !important; aspect-ratio: auto !important; border: 0; }
.hint-badge {
  position: absolute; left: 50%; top: 10px; transform: translateX(-50%); z-index: 5; max-width: calc(100% - 20px);
  background: var(--paper); border: var(--line-width) solid var(--line); padding: 5px 10px;
  font-weight: var(--fw-medium); font-size: 12px; letter-spacing: .04em; text-transform: var(--caps); text-align: center; line-height: 1.3;
  pointer-events: none; animation: badge-pulse 1.1s ease-in-out infinite;
}
@keyframes badge-pulse { 0%, 100% { background: var(--paper); } 50% { background: var(--primary); } }
@media (prefers-reduced-motion: reduce) { .hint-badge { animation: none; background: var(--primary); } }

/* ---------- Buttons & controls ------------------------------------------- */
.controls { display: flex; flex-wrap: wrap; gap: 8px 12px; align-items: center; margin-bottom: 10px; }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px; min-height: 46px; padding: 8px 14px;
  border: var(--line-width) solid var(--line); border-radius: var(--radius); background: var(--paper); color: var(--ink);
  font-weight: var(--fw-medium); font-size: 14px; letter-spacing: .04em; text-transform: var(--caps); text-decoration: none;
  cursor: pointer; user-select: none; -webkit-user-select: none; touch-action: manipulation;
}
.btn:disabled { opacity: .4; cursor: default; }
.btn.primary { background: var(--primary); color: var(--primary-ink); }
.btn[aria-pressed="true"], .btn.active { background: var(--active); color: var(--active-ink); }
.btn.obj[aria-pressed="true"], .btn.obj.active { background: var(--obj); border-color: var(--obj); color: var(--ink-inverse); }
.btn .sub { display: block; font-size: 11px; font-weight: var(--fw-regular); text-transform: none; letter-spacing: 0; }
.btn svg { width: 18px; height: 18px; flex: none; }
.btn.big { min-height: 58px; font-size: 15px; padding: 10px 18px; }
:root[data-view="desktop"] .btn:not(.primary):not([aria-pressed="true"]):not(.active):not(:disabled):hover { background: var(--accent-pale); }
.btn-row { display: flex; gap: 10px; }
.btn-row > .btn { flex: 1; }
.seg { display: flex; flex-wrap: wrap; }
.seg .btn { margin-right: calc(-1 * var(--line-width)); }
.range { display: flex; align-items: center; gap: 12px; flex: 1 1 300px; min-height: 46px; }
.range label, .range .label { font-weight: var(--fw-medium); font-size: 13px; letter-spacing: .04em; text-transform: var(--caps); white-space: nowrap; min-width: 7em; }
.range input[type="range"] { flex: 1; min-width: 0; accent-color: var(--active); height: 32px; }
.range output { font-weight: var(--fw-medium); font-size: 14px; min-width: 5.4em; text-align: right; white-space: nowrap; }
:root[data-view="desktop"] .lab .range { flex-basis: 100%; }
:root[data-view="mobile"] .range { flex-wrap: wrap; gap: 4px 12px; }
:root[data-view="mobile"] .controls .btn { flex: 1 1 auto; }
.readout { font-weight: var(--fw-medium); font-size: 14px; letter-spacing: .04em; text-transform: var(--caps); min-height: 1.5em; margin: 6px 0; }
.readout-grid { display: flex; flex-wrap: wrap; gap: 10px 22px; padding: 12px 0; margin: 10px 0 14px; border-top: var(--line-width) solid var(--line); border-bottom: var(--line-width) solid var(--line); }
.readout-grid > div { font-size: 11px; font-weight: var(--fw-medium); letter-spacing: .08em; text-transform: var(--caps); }
.readout-grid b { display: block; margin-top: 3px; font-size: 20px; font-weight: var(--fw-light); letter-spacing: 0; text-transform: none; }
.hint { font-size: 15px; line-height: 1.5; margin: 8px 0 12px; max-width: 46em; }

/* ---------- Info button ("i" in a circle) + inline note ------------------ */
.info {
  flex: none; display: inline-flex; align-items: center; justify-content: center;
  width: 26px; height: 26px; padding: 0; margin: 0 4px; vertical-align: middle;
  border: var(--line-width) solid var(--line); border-radius: 50%; background: var(--paper); color: var(--ink);
  font-weight: var(--fw-medium); font-size: 14px; font-style: normal; line-height: 1; text-transform: none; cursor: pointer;
}
.info[aria-expanded="true"] { background: var(--active); color: var(--active-ink); }
.info-note { border-left: 4px solid var(--line); background: var(--merke); padding: 10px 12px; margin: 6px 0 12px; font-size: 14px; line-height: 1.5; }
.info-note p + p { margin-top: 6px; }

/* ---------- Tasks + Merke box --------------------------------------------- */
.tasks { border: var(--line-width) solid var(--line); padding: 12px 14px; margin: 12px 0; }
.tasks h3, .merke h3 { font-weight: var(--fw-medium); font-size: 12px; letter-spacing: .08em; text-transform: var(--caps); margin-bottom: 8px; }
.tasks ul { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 8px; }
.tasks li { display: grid; grid-template-columns: 24px 1fr; gap: 8px; font-size: 15px; align-items: start; }
.tasks .box { width: 22px; height: 22px; border: var(--line-width) solid var(--line); background: var(--paper); display: flex; align-items: center; justify-content: center; font-size: 14px; font-weight: var(--fw-medium); }
.tasks li.done .box { background: var(--active); color: var(--active-ink); }
.tasks li.done .box::after { content: "✓"; }
.tasks .status { margin-top: 8px; font-weight: var(--fw-medium); font-size: 13px; letter-spacing: .04em; text-transform: var(--caps); min-height: 1.3em; }
.merke { background: var(--merke); border: var(--line-width) solid var(--line); padding: 12px 14px; margin: 12px 0; }
.merke p { font-size: 16px; line-height: 1.45; }
.merke.locked p { display: none; }
.merke .locked-note { display: none; font-size: 14px; }
.merke.locked .locked-note { display: block; }

/* ---------- Collapsible topics -------------------------------------------- */
.topics { margin: 26px 0 10px; max-width: 900px; }
details.topic { border-top: var(--line-width) solid var(--line); }
details.topic:last-of-type { border-bottom: var(--line-width) solid var(--line); }
details.topic > summary {
  list-style: none; cursor: pointer; display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 14px 0; font-weight: var(--fw-medium); font-size: 17px; line-height: 1.25;
}
details.topic > summary::-webkit-details-marker { display: none; }
details.topic > summary::after { content: "+"; flex: none; width: 26px; height: 26px; border: var(--line-width) solid var(--line); border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 18px; line-height: 1; }
details.topic[open] > summary::after { content: "−"; background: var(--active); color: var(--active-ink); }
.topic-body { padding: 0 0 16px; }
.topic-body p { font-size: 15.5px; line-height: 1.6; margin: 0 0 12px; max-width: 46em; }
.topic-body h3 { font-weight: var(--fw-medium); font-size: 16px; margin: 14px 0 8px; }
.topic-body ol, .topic-body ul { padding-left: 22px; margin: 0 0 12px; }
.topic-body li { font-size: 15.5px; line-height: 1.55; margin-bottom: 6px; }

/* ---------- Strip of many items + pager ----------------------------------- */
.strip { display: flex; overflow-x: auto; border-top: var(--line-width) solid var(--line); border-bottom: var(--line-width) solid var(--line); scrollbar-width: thin; background: var(--paper); }
.strip a, .strip button { flex: 0 0 auto; display: flex; align-items: center; gap: 8px; min-height: 44px; padding: 6px 12px; border: 0; border-right: var(--line-width) solid var(--line); background: var(--paper); text-decoration: none; font-weight: var(--fw-medium); font-size: 12.5px; letter-spacing: .05em; text-transform: var(--caps); white-space: nowrap; cursor: pointer; }
.strip [aria-current="true"], .strip [aria-pressed="true"] { background: var(--active); color: var(--active-ink); }
.pager { display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); gap: 8px; margin-top: 24px; }
.pager .btn { min-height: 54px; min-width: 0; }
.pager .prev { justify-content: flex-start; }
.pager .next { justify-content: flex-end; }
.pager .t { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.next-part { display: flex; justify-content: flex-end; margin: 24px 0 0; }
:root[data-view="mobile"] .pager { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
:root[data-view="mobile"] .pager .home { grid-column: 1 / -1; order: -1; }

/* ---------- Stepper (steps inside one simulation) ------------------------- */
.stepper { list-style: none; margin: 0 0 12px; padding: 0; display: grid; grid-template-columns: repeat(auto-fit, minmax(110px, 1fr)); gap: 6px; }
.stepper button { width: 100%; min-height: 44px; border: var(--line-width) solid var(--line); background: var(--paper); font-weight: var(--fw-medium); font-size: 13px; text-align: left; padding: 8px 10px; cursor: pointer; }
.stepper button.done { background: var(--accent-pale); }
.stepper button[aria-current="step"] { background: var(--active); color: var(--active-ink); }
:root[data-view="desktop"] .lab .stepper { grid-template-columns: 1fr; }

/* ---------- Footer -------------------------------------------------------- */
.foot { background: var(--foot-bg); color: var(--foot-ink); padding: 26px var(--gutter) 30px; }
.foot .sources { font-size: 13px; line-height: 1.5; max-width: 60em; margin-bottom: 14px; }
.foot .brand-line { font-weight: var(--fw-medium); font-size: 15px; letter-spacing: .04em; }
.dev-link { display: inline-block; margin-top: 10px; border: 0; background: none; padding: 4px 0; color: inherit; font-size: 11px; opacity: .3; cursor: pointer; }

/* ---------- Tables, chips, misc ------------------------------------------- */
.chip { display: inline-flex; align-items: center; gap: 6px; padding: 4px 10px; border: var(--line-width) solid var(--line); font-weight: var(--fw-medium); font-size: 12px; letter-spacing: .04em; text-transform: var(--caps); }
.muted { color: var(--ink-muted); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }