/* ============================================================
   TRACHTENBERG — laboratoire de calcul
   Dark rétro-futuriste : phosphore cyan, retenues ambre, +5 magenta.
   ============================================================ */

:root {
  --bg: #05070d;
  --bg2: #0a0f1b;
  --panel: #0c1220;
  --panel-edge: #1b2740;
  --ink: #e8eefc;
  --ink-dim: #93a1bd;
  --ink-faint: #55617c;
  --acc: #3df5b8;        /* phosphore */
  --acc-dim: #1b6e56;
  --amber: #ffb02e;      /* retenues */
  --magenta: #ff5c8a;    /* +5 impair / erreurs */
  --blue: #7fd4ff;       /* voisin */
  --font-display: "Unbounded", sans-serif;
  --font-body: "Sora", sans-serif;
  --font-mono: "IBM Plex Mono", monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

.mono { font-family: var(--font-mono); }

::selection { background: var(--acc); color: var(--bg); }

/* ---------- fond : grille + halo ---------- */
.bg-grid {
  position: fixed; inset: 0; z-index: -2;
  background-image:
    linear-gradient(rgba(61, 245, 184, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(61, 245, 184, 0.045) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: radial-gradient(ellipse 90% 70% at 50% 0%, #000 30%, transparent 100%);
}
.bg-glow {
  position: fixed; z-index: -1;
  top: -30vh; left: 50%; transform: translateX(-50%);
  width: 110vw; height: 70vh;
  background: radial-gradient(ellipse at center,
    rgba(61, 245, 184, 0.10), rgba(127, 212, 255, 0.05) 45%, transparent 70%);
  pointer-events: none;
}

/* ---------- header ---------- */
.top {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; flex-wrap: wrap;
  max-width: 1060px; margin: 0 auto; padding: 1.4rem 1.5rem;
}
.logo { display: flex; align-items: center; gap: 0.8rem; text-decoration: none; color: var(--ink); }
.logo-mark {
  display: grid; place-items: center;
  width: 2.6rem; height: 2.6rem;
  border: 1px solid var(--acc); border-radius: 8px;
  color: var(--acc); font-size: 1.5rem; font-weight: 600;
  box-shadow: 0 0 18px rgba(61, 245, 184, 0.35), inset 0 0 10px rgba(61, 245, 184, 0.12);
  text-shadow: 0 0 8px var(--acc);
}
.logo-text {
  font-family: var(--font-display); font-weight: 800; font-size: 0.95rem;
  letter-spacing: 0.14em; display: flex; flex-direction: column; line-height: 1.25;
}
.logo-sub {
  font-family: var(--font-mono); font-weight: 400; font-size: 0.6rem;
  letter-spacing: 0.32em; color: var(--acc); text-transform: uppercase;
}
.nav { display: flex; gap: 0.3rem; flex-wrap: wrap; }
.nav a {
  color: var(--ink-dim); text-decoration: none; font-size: 0.88rem;
  padding: 0.45rem 0.9rem; border-radius: 999px; border: 1px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}
.nav a:hover { color: var(--ink); }
.nav a.nav--on { color: var(--acc); border-color: var(--acc-dim); }
.nav-play { border: 1px solid var(--panel-edge) !important; }
.nav-play::before { content: "▶ "; color: var(--acc); font-size: 0.7em; }

/* ---------- layout ---------- */
main { max-width: 1060px; margin: 0 auto; padding: 1rem 1.5rem 4rem; }
.page-enter { animation: pageIn 0.45s cubic-bezier(0.2, 0.7, 0.2, 1) both; }
@keyframes pageIn { from { opacity: 0; transform: translateY(14px); } }

h1 {
  font-family: var(--font-display); font-weight: 800;
  font-size: clamp(1.7rem, 4.5vw, 2.7rem); line-height: 1.15;
  margin: 0.4rem 0 1.2rem; letter-spacing: 0.01em;
}
h2 {
  font-family: var(--font-display); font-weight: 600; font-size: 1.15rem;
  margin: 2.6rem 0 1rem; letter-spacing: 0.03em;
}
h2 .h2-calc { color: var(--acc); font-size: 1rem; margin-left: 0.6rem; }
.kicker {
  font-family: var(--font-mono); font-size: 0.75rem; letter-spacing: 0.22em;
  text-transform: uppercase; color: var(--acc);
  display: flex; align-items: center; gap: 0.8rem;
}
.glow { color: var(--acc); text-shadow: 0 0 24px rgba(61, 245, 184, 0.55); }
.lede { color: var(--ink-dim); max-width: 58ch; }
.lede b { color: var(--ink); }

.panel {
  background: linear-gradient(180deg, var(--panel), var(--bg2));
  border: 1px solid var(--panel-edge);
  border-radius: 14px;
  padding: 1.4rem;
  position: relative;
}
.panel::before {
  content: ""; position: absolute; top: 0; left: 12px; right: 12px; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(61, 245, 184, 0.4), transparent);
}

.label {
  font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.25em;
  text-transform: uppercase; color: var(--ink-faint); margin-bottom: 0.5rem;
}
.dots { color: var(--acc); letter-spacing: 0.2em; font-size: 0.7rem; }

/* ---------- boutons ---------- */
.btn {
  font-family: var(--font-body); font-size: 0.9rem; font-weight: 600;
  color: var(--ink); background: transparent;
  border: 1px solid var(--panel-edge); border-radius: 10px;
  padding: 0.6rem 1.1rem; cursor: pointer; text-decoration: none;
  display: inline-flex; align-items: center; gap: 0.5rem;
  transition: border-color 0.2s, box-shadow 0.2s, transform 0.08s;
}
.btn:hover { border-color: var(--acc-dim); }
.btn:active { transform: translateY(1px); }
.btn--primary {
  background: var(--acc); color: #04150e; border-color: var(--acc);
  box-shadow: 0 0 22px rgba(61, 245, 184, 0.35);
}
.btn--primary:hover { box-shadow: 0 0 34px rgba(61, 245, 184, 0.55); border-color: var(--acc); }
.btn--lg { padding: 0.85rem 1.5rem; font-size: 1rem; border-radius: 12px; }
.btn--icon { padding: 0.6rem 0.8rem; }
.btn:disabled { opacity: 0.35; cursor: default; }

input.mono, .answer, .exo-in, .lab-controls input, .proof-inputs input {
  background: #060b14; color: var(--ink);
  border: 1px solid var(--panel-edge); border-radius: 10px;
  font-family: var(--font-mono); font-size: 1.05rem;
  padding: 0.6rem 0.9rem; outline: none; min-width: 0;
  transition: border-color 0.2s, box-shadow 0.2s;
}
input.mono:focus, .answer:focus, .exo-in:focus, .proof-inputs input:focus {
  border-color: var(--acc); box-shadow: 0 0 0 3px rgba(61, 245, 184, 0.15);
}

/* ---------- hero ---------- */
.hero {
  display: grid; grid-template-columns: 1.05fr 1fr; gap: 2.2rem;
  align-items: center; padding: 2.5rem 0 1rem;
}
.hero-copy > * + * { margin-top: 1.1rem; }
.hero-cta { display: flex; gap: 0.8rem; flex-wrap: wrap; }
.hero-demo { animation: heroIn 0.8s 0.15s cubic-bezier(0.2, 0.7, 0.2, 1) both; }
@keyframes heroIn { from { opacity: 0; transform: translateX(26px) scale(0.98); } }

.home-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: 1rem; margin-top: 2.5rem;
}
.card {
  display: block; text-decoration: none; color: var(--ink);
  background: linear-gradient(180deg, var(--panel), var(--bg2));
  border: 1px solid var(--panel-edge); border-radius: 14px; padding: 1.3rem;
  transition: border-color 0.25s, transform 0.25s, box-shadow 0.25s;
}
.card:hover {
  border-color: var(--acc-dim); transform: translateY(-4px);
  box-shadow: 0 12px 34px rgba(0, 0, 0, 0.45), 0 0 24px rgba(61, 245, 184, 0.08);
}
.card-num {
  font-family: var(--font-mono); color: var(--acc); font-size: 0.75rem;
  letter-spacing: 0.3em; margin-bottom: 0.7rem;
}
.card h3 { font-family: var(--font-display); font-size: 1rem; font-weight: 600; margin-bottom: 0.4rem; }
.card p { color: var(--ink-dim); font-size: 0.86rem; }

/* ---------- visualiseur ---------- */
.viz-stage { display: flex; flex-direction: column; gap: 0.9rem; align-items: center; padding: 0.6rem 0 1rem; }
.viz-row { display: flex; gap: 0.45rem; flex-wrap: wrap; justify-content: center; }
.cell {
  display: grid; place-items: center;
  width: 3rem; height: 3.6rem;
  font-family: var(--font-mono); font-size: 1.7rem; font-weight: 600;
  background: #060b14; border: 1px solid var(--panel-edge); border-radius: 10px;
  transition: border-color 0.25s, box-shadow 0.25s, color 0.25s, background 0.25s;
}
.viz--compact .cell { width: 2.4rem; height: 3rem; font-size: 1.35rem; }
.cell--ghost { color: var(--ink-faint); border-style: dashed; }
.cell--digit {
  border-color: var(--acc); color: var(--acc);
  box-shadow: 0 0 16px rgba(61, 245, 184, 0.45), inset 0 0 10px rgba(61, 245, 184, 0.12);
  text-shadow: 0 0 10px var(--acc);
}
.cell--neighbor {
  border-color: var(--blue); color: var(--blue);
  box-shadow: 0 0 14px rgba(127, 212, 255, 0.35);
}
.cell--out { border-style: dotted; color: var(--ink-faint); }
.cell--filled {
  border-style: solid; color: var(--acc); border-color: var(--acc-dim);
  background: rgba(61, 245, 184, 0.05); text-shadow: 0 0 8px rgba(61, 245, 184, 0.6);
}
.cell--pop { animation: pop 0.35s cubic-bezier(0.2, 1.4, 0.4, 1); }
@keyframes pop { 0% { transform: scale(0.5); } 100% { transform: scale(1); } }

.viz-formula { min-height: 4.6rem; display: flex; flex-direction: column; gap: 0.45rem; align-items: center; justify-content: center; text-align: center; }
.viz-formula-line { display: flex; align-items: center; gap: 0.4rem; flex-wrap: wrap; justify-content: center; }
.viz-hint, .viz-done { color: var(--ink-dim); font-size: 0.9rem; }
.viz-done b { color: var(--acc); font-family: var(--font-mono); }

.chip {
  font-family: var(--font-mono); font-size: 0.8rem;
  border: 1px solid var(--panel-edge); border-radius: 999px;
  padding: 0.22rem 0.7rem; color: var(--ink-dim); white-space: nowrap;
}
.chip b { color: var(--ink); }
.chip--odd { border-color: var(--magenta); color: var(--magenta); }
.chip--odd b { color: var(--magenta); }
.chip--carry { border-color: var(--amber); color: var(--amber); }
.chip--carry b { color: var(--amber); }
.chip--neg { border-color: var(--magenta); }
.chip--sum { border-color: var(--acc); }
.chip--sum b { color: var(--acc); font-size: 1rem; }
.chip--write { background: rgba(61, 245, 184, 0.1); border-color: var(--acc); }
.chip--write b { color: var(--acc); font-size: 1rem; text-shadow: 0 0 8px rgba(61, 245, 184, 0.6); }
.chip--zero { opacity: 0.5; }
.chip-plus, .chip-eq { color: var(--ink-faint); font-family: var(--font-mono); }
.chip-eq { color: var(--acc); }

.viz-controls {
  display: flex; gap: 0.6rem; align-items: center; justify-content: center; flex-wrap: wrap;
  border-top: 1px dashed var(--panel-edge); padding-top: 1rem;
}
.viz-speed { display: flex; align-items: center; gap: 0.5rem; color: var(--ink-faint); font-size: 0.75rem; font-family: var(--font-mono); }
.viz-speed input { accent-color: var(--acc); width: 90px; }

/* ---------- méthode ---------- */
.history { display: flex; gap: 1.4rem; align-items: flex-start; margin: 1.2rem 0 0; }
.history-mark {
  color: var(--amber); font-size: 0.8rem; letter-spacing: 0.15em;
  border: 1px solid rgba(255, 176, 46, 0.4); border-radius: 8px; padding: 0.3rem 0.6rem;
  white-space: nowrap;
}
.history p { color: var(--ink-dim); font-size: 0.95rem; }

.principles { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); gap: 0.9rem; }
.principle {
  background: linear-gradient(180deg, var(--panel), var(--bg2));
  border: 1px solid var(--panel-edge); border-radius: 12px; padding: 1.1rem;
  animation: pageIn 0.5s calc(var(--i) * 0.07s) both;
}
.principle-icon {
  color: var(--acc); font-size: 1.3rem; width: 2.4rem; height: 2.4rem;
  display: grid; place-items: center; border: 1px dashed var(--acc-dim);
  border-radius: 8px; margin-bottom: 0.7rem;
}
.principle h3 { font-size: 0.92rem; font-weight: 600; margin-bottom: 0.3rem; }
.principle p { font-size: 0.82rem; color: var(--ink-dim); }

.families { display: flex; flex-direction: column; gap: 1.1rem; }
.family {
  border: 1px solid var(--panel-edge); border-radius: 14px; padding: 1.2rem;
  background: linear-gradient(180deg, var(--panel), var(--bg2));
  animation: pageIn 0.5s calc(var(--i) * 0.08s) both;
}
.family-head { display: flex; align-items: baseline; gap: 1rem; flex-wrap: wrap; margin-bottom: 0.9rem; }
.family-head h3 { font-family: var(--font-display); font-size: 1rem; font-weight: 600; }
.family-head p { color: var(--ink-faint); font-size: 0.82rem; }
.family-rules { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 0.7rem; }
.rulecard {
  display: flex; align-items: center; gap: 0.9rem; text-decoration: none;
  border: 1px solid var(--panel-edge); border-radius: 10px; padding: 0.8rem 1rem;
  color: var(--ink); transition: border-color 0.2s, background 0.2s;
}
.rulecard:hover { border-color: var(--acc-dim); background: rgba(61, 245, 184, 0.04); }
.rulecard-k {
  color: var(--acc); font-weight: 600; font-size: 1.1rem; min-width: 2.9rem;
  text-shadow: 0 0 10px rgba(61, 245, 184, 0.4);
}
.rulecard-sum { flex: 1; color: var(--ink-dim); font-size: 0.78rem; line-height: 1.4; }

/* ---------- leçon ---------- */
.rulebox { margin: 0.5rem 0 1.2rem; border-color: var(--acc-dim); }
.rulebox::before { background: linear-gradient(90deg, transparent, var(--acc), transparent); }
.rulebox-label {
  font-family: var(--font-mono); font-size: 0.65rem; letter-spacing: 0.35em;
  color: var(--acc); margin-bottom: 0.5rem;
}
.rulebox-text { font-size: 1.15rem; line-height: 1.5; }
.rulebox-text b { color: var(--acc); }
.lesson-detail { color: var(--ink-dim); max-width: 62ch; }

.why { margin-top: 1.2rem; border: 1px dashed var(--panel-edge); border-radius: 12px; padding: 1rem 1.2rem; }
.why summary {
  cursor: pointer; font-family: var(--font-mono); font-size: 0.8rem;
  letter-spacing: 0.15em; text-transform: uppercase; color: var(--amber);
}
.why p { margin-top: 0.8rem; color: var(--ink-dim); font-size: 0.92rem; max-width: 62ch; }
.why i { color: var(--ink); font-family: var(--font-mono); font-style: normal; }

.exercises { display: flex; flex-direction: column; gap: 0.7rem; }
.exo { display: flex; align-items: center; gap: 1rem; padding: 0.9rem 1.2rem; flex-wrap: wrap; }
.exo-q { font-size: 1.1rem; color: var(--ink); }
.exo-in { flex: 1; min-width: 130px; max-width: 220px; }
.exo-mark { font-size: 1.2rem; width: 1.6rem; }
.exo--ok { border-color: var(--acc); }
.exo--ok .exo-mark { color: var(--acc); }
.exo--ko { border-color: rgba(255, 92, 138, 0.5); }
.exo--ko .exo-mark { color: var(--magenta); }

.pager { display: flex; justify-content: space-between; gap: 1rem; margin-top: 2.6rem; flex-wrap: wrap; }

/* ---------- labo ---------- */
.lab-controls { display: flex; gap: 1.6rem; flex-wrap: wrap; margin: 1.4rem 0 1rem; }
.lab-controls label {
  display: flex; flex-direction: column; gap: 0.45rem;
  font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.22em;
  text-transform: uppercase; color: var(--ink-faint);
}
.lab-controls input { font-size: 1.3rem; width: 12ch; letter-spacing: 0.1em; }

.rulepick, .sizepick { display: flex; gap: 0.4rem; flex-wrap: wrap; }
.pick {
  font-family: var(--font-mono); font-size: 0.85rem; cursor: pointer;
  background: #060b14; color: var(--ink-dim);
  border: 1px solid var(--panel-edge); border-radius: 8px; padding: 0.4rem 0.7rem;
  transition: all 0.15s;
}
.pick:hover { border-color: var(--acc-dim); color: var(--ink); }
.pick--on {
  border-color: var(--acc); color: var(--acc);
  box-shadow: 0 0 12px rgba(61, 245, 184, 0.25); text-shadow: 0 0 8px rgba(61, 245, 184, 0.5);
}

/* ---------- preuves ---------- */
.proof-panel { margin-top: 1.6rem; }
.proof-inputs { display: flex; gap: 0.7rem; align-items: center; flex-wrap: wrap; }
.proof-inputs input { width: 9ch; font-size: 1.15rem; }
.proof-inputs input#pc { width: 13ch; }
.proof-op { color: var(--acc); font-size: 1.3rem; }
.proof-out { margin-top: 1.3rem; display: flex; flex-direction: column; gap: 0.6rem; }
.proof-line {
  display: flex; align-items: center; gap: 1rem; flex-wrap: wrap;
  border: 1px solid var(--panel-edge); border-radius: 10px; padding: 0.7rem 1rem;
  font-size: 0.9rem;
}
.proof-badge {
  font-size: 0.7rem; letter-spacing: 0.2em; text-transform: uppercase;
  border: 1px solid currentColor; border-radius: 999px; padding: 0.15rem 0.6rem;
}
.proof--ok { border-color: var(--acc-dim); }
.proof--ok .proof-badge, .proof--ok .proof-verdict { color: var(--acc); }
.proof--ko { border-color: rgba(255, 92, 138, 0.5); }
.proof--ko .proof-badge, .proof--ko .proof-verdict { color: var(--magenta); }
.proof-verdict { margin-left: auto; font-weight: 600; }
.proof-note { color: var(--ink-dim); font-size: 0.85rem; padding: 0.2rem 0.3rem; }

/* ---------- arcade ---------- */
.arcade { display: flex; flex-direction: column; gap: 1.1rem; position: relative; }
.arcade-setup { display: flex; gap: 2rem; flex-wrap: wrap; }
.arcade-hud {
  display: flex; gap: 1.6rem; align-items: center; flex-wrap: wrap;
  padding: 0.4rem 0.2rem;
}
.hud-level { flex: 1; min-width: 220px; }
.hud-level-name {
  font-family: var(--font-display); font-size: 0.85rem; font-weight: 600;
  letter-spacing: 0.06em; margin-bottom: 0.4rem;
}
.xpbar {
  height: 8px; background: #060b14; border: 1px solid var(--panel-edge);
  border-radius: 999px; overflow: hidden;
}
.xpbar-fill {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--acc-dim), var(--acc));
  box-shadow: 0 0 12px rgba(61, 245, 184, 0.6);
  transition: width 0.6s cubic-bezier(0.2, 0.7, 0.2, 1);
}
.hud-xp { font-size: 0.72rem; color: var(--ink-faint); margin-top: 0.3rem; }
.hud-stat {
  display: flex; flex-direction: column; align-items: center; gap: 0.1rem;
  font-size: 0.68rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--ink-faint);
}
.hud-num { font-size: 1.6rem; color: var(--amber); text-shadow: 0 0 12px rgba(255, 176, 46, 0.4); }

.arcade-play { text-align: center; padding: 2rem 1.4rem; }
.question {
  font-size: clamp(1.6rem, 5vw, 2.6rem); font-weight: 600; letter-spacing: 0.04em;
  color: var(--ink); text-shadow: 0 0 24px rgba(61, 245, 184, 0.25);
  margin-bottom: 1.2rem; min-height: 1.2em;
}
.answer-form { display: flex; gap: 0.7rem; justify-content: center; flex-wrap: wrap; }
.answer { font-size: 1.3rem; width: 15ch; text-align: center; letter-spacing: 0.08em; }
.verdict { min-height: 1.8rem; margin-top: 1rem; font-size: 0.95rem; font-weight: 600; }
.verdict--ok { color: var(--acc); text-shadow: 0 0 12px rgba(61, 245, 184, 0.5); }
.verdict--ko { color: var(--magenta); }
.verdict--hint { color: var(--amber); font-weight: 400; font-size: 0.88rem; }

.badge-grid { display: flex; gap: 0.6rem; flex-wrap: wrap; }
.badge {
  display: flex; align-items: center; gap: 0.5rem;
  border: 1px solid var(--panel-edge); border-radius: 999px;
  padding: 0.35rem 0.9rem; font-size: 0.78rem; color: var(--ink-faint);
  filter: grayscale(1); opacity: 0.55; transition: all 0.4s;
}
.badge--on {
  filter: none; opacity: 1; color: var(--ink);
  border-color: var(--amber); box-shadow: 0 0 14px rgba(255, 176, 46, 0.2);
}
.badge-icon { color: var(--amber); }
.confetti { position: absolute; top: 0; left: 0; width: 100%; pointer-events: none; display: none; z-index: 5; }

/* ---------- footer ---------- */
.foot {
  max-width: 1060px; margin: 0 auto; padding: 1.6rem 1.5rem 2.4rem;
  display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap;
  color: var(--ink-faint); font-size: 0.75rem;
  border-top: 1px solid var(--panel-edge);
}
.foot .mono { color: var(--acc-dim); }

/* ---------- responsive ---------- */
@media (max-width: 820px) {
  .hero { grid-template-columns: 1fr; padding-top: 1rem; }
  .cell { width: 2.3rem; height: 2.9rem; font-size: 1.3rem; }
  .viz--compact .cell { width: 2rem; height: 2.6rem; font-size: 1.15rem; }
  .history { flex-direction: column; gap: 0.8rem; }
  .proof-verdict { margin-left: 0; width: 100%; }
}