/* ==========================================================================
   Cours-Interactif — thème « 3Blue1Brown »
   Palette inspirée de manim : fond quasi noir, couleurs vives et saturées.
   ========================================================================== */
:root {
  --bg: #0b0c10;
  --bg-2: #111318;
  --panel: #15181f;
  --panel-2: #1b1f28;
  --line: #2a2f3b;
  --line-2: #3a4152;
  --text: #e8e6e3;
  --text-dim: #a4a9b4;
  --text-faint: #6b7280;

  /* couleurs manim */
  --blue: #58c4dd;
  --blue-d: #29abca;
  --teal: #5cd0b3;
  --green: #83c167;
  --yellow: #ffff00;
  --yellow-s: #f4d345;
  --gold: #f0ac5f;
  --red: #fc6255;
  --maroon: #c55f73;
  --purple: #9a72ac;
  --pink: #d147bd;
  --grey: #888888;

  /* sources */
  --src-slides: #58c4dd;
  --src-book: #f0ac5f;
  --src-extra: #d147bd;
  --src-hw: #83c167;

  --radius: 10px;
  --sidebar-w: 270px;
  --content-w: 1120px;
  --font-ui: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, sans-serif;
  --font-serif: "KaTeX_Main", "Latin Modern Roman", "CMU Serif", Georgia, serif;
  --font-mono: "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-ui);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }
::selection { background: rgba(88, 196, 221, 0.35); }

/* ---------- barre du haut ---------- */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 18px;
  height: 52px; padding: 0 20px;
  background: rgba(11, 12, 16, 0.88);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.topbar .brand {
  font-family: var(--font-serif); font-size: 20px; color: var(--text);
  display: flex; align-items: center; gap: 10px; white-space: nowrap;
}
.topbar .brand .pi {
  display: inline-grid; place-items: center;
  width: 28px; height: 28px; border-radius: 50%;
  background: var(--blue-d); color: #0b0c10; font-weight: 700; font-size: 16px;
}
.topbar nav { display: flex; gap: 4px; overflow-x: auto; }
.topbar nav a {
  padding: 6px 12px; border-radius: 6px; color: var(--text-dim); font-size: 14px; white-space: nowrap;
}
.topbar nav a:hover { background: var(--panel-2); color: var(--text); text-decoration: none; }
.topbar nav a.active { color: var(--yellow-s); background: var(--panel); }
.topbar nav a.soon { opacity: 0.45; pointer-events: none; }
.topbar .spacer { flex: 1; }
.topbar .legend-btn { font-size: 13px; color: var(--text-dim); cursor: pointer; }

/* ---------- mise en page chapitre ---------- */
.layout { display: flex; }
.sidebar {
  position: sticky; top: 52px; align-self: flex-start;
  width: var(--sidebar-w); height: calc(100vh - 52px); overflow-y: auto;
  padding: 22px 14px 40px 20px;
  border-right: 1px solid var(--line);
  font-size: 13.5px;
}
.sidebar h4 { margin: 0 0 10px; font-size: 11px; letter-spacing: .12em; text-transform: uppercase; color: var(--text-faint); }
.sidebar a { display: block; padding: 4px 8px; border-radius: 5px; color: var(--text-dim); line-height: 1.35; }
.sidebar a.l2 { padding-left: 22px; font-size: 12.5px; color: var(--text-faint); }
.sidebar a:hover { background: var(--panel); text-decoration: none; color: var(--text); }
.sidebar a.current { color: var(--yellow-s); background: var(--panel); }
.sidebar .legend { margin-top: 26px; padding-top: 14px; border-top: 1px solid var(--line); }
.sidebar .legend div { display: flex; align-items: center; gap: 8px; margin: 6px 0; color: var(--text-dim); font-size: 12.5px; }

main.content { flex: 1; min-width: 0; padding: 30px 40px 120px; }
.content-inner { max-width: var(--content-w); margin: 0 auto; }

h1, h2, h3 { font-family: var(--font-serif); font-weight: 400; letter-spacing: .01em; }
h1 { font-size: 44px; margin: 10px 0 6px; color: var(--text); }
h1 .sub { display: block; font-size: 20px; color: var(--text-dim); margin-top: 6px; }
h2 {
  font-size: 32px; margin: 80px 0 14px; padding-top: 18px; color: var(--blue);
  border-top: 1px solid var(--line); scroll-margin-top: 70px;
}
h2 .num { color: var(--text-faint); margin-right: 12px; }
h3 { font-size: 23px; margin: 44px 0 10px; color: var(--yellow-s); scroll-margin-top: 70px; }
h4 { font-size: 16px; margin: 26px 0 8px; color: var(--teal); }
p { margin: 10px 0; }
strong { color: #fff; }
em { color: var(--text); }
ul, ol { padding-left: 22px; }
li { margin: 4px 0; }
code { font-family: var(--font-mono); font-size: 0.88em; background: var(--panel-2); padding: 1px 5px; border-radius: 4px; color: var(--gold); }
hr { border: 0; border-top: 1px solid var(--line); margin: 30px 0; }

.c-blue { color: var(--blue); } .c-teal { color: var(--teal); } .c-green { color: var(--green); }
.c-yellow { color: var(--yellow-s); } .c-gold { color: var(--gold); } .c-red { color: var(--red); }
.c-maroon { color: var(--maroon); } .c-purple { color: var(--purple); } .c-pink { color: var(--pink); }
.c-dim { color: var(--text-dim); }

/* ---------- badges de source ---------- */
.src {
  display: inline-flex; align-items: center; gap: 5px;
  font-family: var(--font-ui); font-size: 11.5px; font-weight: 600; letter-spacing: .02em;
  padding: 2px 8px; border-radius: 999px; vertical-align: middle; margin: 0 2px;
  border: 1px solid currentColor; white-space: nowrap; line-height: 1.5;
}
.src::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: currentColor; }
.src.slides { color: var(--src-slides); background: rgba(88,196,221,.08); }
.src.book { color: var(--src-book); background: rgba(240,172,95,.08); }
.src.extra { color: var(--src-extra); background: rgba(209,71,189,.10); }
.src.hw { color: var(--src-hw); background: rgba(131,193,103,.08); }
a.src:hover { text-decoration: none; filter: brightness(1.25); }
.sources { margin: -4px 0 14px; display: flex; flex-wrap: wrap; gap: 6px; }

/* bloc entièrement hors slides */
.extra-block {
  border-left: 3px solid var(--src-extra);
  background: linear-gradient(90deg, rgba(209,71,189,.07), transparent 60%);
  padding: 4px 0 4px 18px; margin: 18px 0;
}

/* ---------- encadrés ---------- */
.box {
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 14px 20px; margin: 18px 0; position: relative;
}
.box > .box-title {
  font-size: 12px; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; margin-bottom: 6px;
}
.box.def { border-left: 3px solid var(--blue); } .box.def > .box-title { color: var(--blue); }
.box.thm { border-left: 3px solid var(--yellow-s); } .box.thm > .box-title { color: var(--yellow-s); }
.box.intu { border-left: 3px solid var(--green); } .box.intu > .box-title { color: var(--green); }
.box.warn { border-left: 3px solid var(--red); } .box.warn > .box-title { color: var(--red); }
.box.q { border-left: 3px solid var(--purple); } .box.q > .box-title { color: var(--purple); }
.box.hw { border-left: 3px solid var(--src-hw); } .box.hw > .box-title { color: var(--src-hw); }

/* ---------- preuves repliables ---------- */
details.proof {
  margin: 14px 0; border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--bg-2); overflow: hidden;
}
details.proof > summary {
  cursor: pointer; list-style: none; padding: 10px 16px; user-select: none;
  display: flex; align-items: center; gap: 10px; color: var(--gold); font-weight: 600; font-size: 14.5px;
}
details.proof > summary::-webkit-details-marker { display: none; }
details.proof > summary::before {
  content: "▸"; display: inline-block; transition: transform .2s; color: var(--gold);
}
details.proof[open] > summary::before { transform: rotate(90deg); }
details.proof > summary .hint { margin-left: auto; font-weight: 400; font-size: 12px; color: var(--text-faint); }
details.proof > .proof-body { padding: 4px 22px 16px; border-top: 1px solid var(--line); }
.proof-body .step { margin: 12px 0; padding-left: 14px; border-left: 2px solid var(--line-2); }
.proof-body .step .why { color: var(--text-faint); font-size: 13.5px; }
.proof-body .qed { text-align: right; color: var(--text-faint); }
.proof-controls { display: flex; gap: 8px; margin: 10px 0 0; }
.proof-body.stepped .step { display: none; }
.proof-body.stepped .step.shown { display: block; animation: fadein .35s ease; }
@keyframes fadein { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

/* ---------- équations ---------- */
.katex { font-size: 1.08em; }
.katex-display { margin: 14px 0; overflow-x: auto; overflow-y: hidden; padding: 4px 0; }
.eq-card {
  background: var(--panel); border-radius: var(--radius); padding: 6px 18px; margin: 14px 0;
  border: 1px solid var(--line);
}

/* ---------- widgets / scènes ---------- */
.widget {
  margin: 22px 0 26px; border: 1px solid var(--line); border-radius: 14px;
  background: #000; overflow: hidden;
}
.widget-head {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 14px; border-bottom: 1px solid var(--line); background: var(--bg-2);
  font-size: 13px; color: var(--text-dim);
}
.widget-head .w-title { color: var(--text); font-weight: 600; }
.widget-head .w-tag {
  font-size: 10.5px; font-weight: 700; letter-spacing: .08em; padding: 1px 7px; border-radius: 4px;
  background: var(--panel-2); color: var(--teal);
}
.widget-head .w-tag.d3 { color: var(--pink); }
.widget-head .spacer { flex: 1; }
.widget-body { display: flex; flex-wrap: wrap; }
.widget-views { flex: 1 1 520px; min-width: 0; display: flex; flex-wrap: wrap; }
.view { position: relative; flex: 1 1 320px; min-width: 0; height: 420px; border-right: 1px solid #111; }
.view:last-child { border-right: 0; }
.view.tall { height: 520px; }
.view.short { height: 300px; }
.view canvas { display: block; width: 100%; height: 100%; touch-action: none; }
.view .view-label {
  position: absolute; top: 8px; left: 10px; font-size: 12px; color: var(--text-faint);
  pointer-events: none; font-family: var(--font-ui); z-index: 3;
}
.view .view-hint {
  position: absolute; bottom: 6px; right: 10px; font-size: 11px; color: var(--text-faint);
  pointer-events: none; z-index: 3;
}
.overlay { position: absolute; inset: 0; pointer-events: none; overflow: hidden; z-index: 2; }
.overlay .lbl {
  position: absolute; transform: translate(-50%, -50%); white-space: nowrap;
  font-size: 14px; text-shadow: 0 0 4px #000, 0 0 8px #000;
}
.overlay .lbl .katex { font-size: 1em; }

.controls {
  flex: 0 0 280px; padding: 14px 16px; background: var(--bg-2); border-left: 1px solid var(--line);
  display: flex; flex-direction: column; gap: 11px; font-size: 13px; max-height: 620px; overflow-y: auto;
}
.controls.wide { flex-basis: 100%; border-left: 0; border-top: 1px solid var(--line); flex-direction: row; flex-wrap: wrap; max-height: none; }
.controls.wide .ctl { flex: 1 1 220px; }
.ctl label { display: flex; justify-content: space-between; align-items: baseline; gap: 8px; color: var(--text-dim); }
.ctl label .val { font-family: var(--font-mono); color: var(--yellow-s); font-size: 12.5px; }
.ctl input[type=range] { width: 100%; accent-color: var(--blue); margin: 4px 0 0; }
.ctl select {
  width: 100%; background: var(--panel-2); color: var(--text); border: 1px solid var(--line-2);
  border-radius: 6px; padding: 5px 8px; font-size: 13px; margin-top: 4px;
}
.ctl.check label { justify-content: flex-start; cursor: pointer; }
.ctl.check input { accent-color: var(--teal); }
.btn-row { display: flex; flex-wrap: wrap; gap: 6px; }
.btn {
  background: var(--panel-2); color: var(--text); border: 1px solid var(--line-2); border-radius: 6px;
  padding: 5px 11px; font-size: 12.5px; cursor: pointer; font-family: var(--font-ui);
}
.btn:hover { border-color: var(--blue); color: #fff; }
.btn.primary { background: var(--blue-d); border-color: var(--blue-d); color: #041016; font-weight: 600; }
.btn.primary:hover { filter: brightness(1.1); }
.btn.on { border-color: var(--yellow-s); color: var(--yellow-s); }
.readout {
  background: #000; border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px;
  font-size: 13px; line-height: 1.55; color: var(--text-dim);
}
.readout .k { color: var(--text-faint); }
.readout b { color: var(--yellow-s); font-weight: 500; font-family: var(--font-mono); }
.ctl-sep { border-top: 1px solid var(--line); margin: 2px 0; }
.ctl-title { font-size: 11px; text-transform: uppercase; letter-spacing: .1em; color: var(--text-faint); }
.widget-foot {
  padding: 9px 14px; border-top: 1px solid var(--line); background: var(--bg-2);
  font-size: 13px; color: var(--text-dim);
}
.widget-foot .katex { font-size: 1em; }

/* légende colorée dans les widgets */
.key { display: inline-flex; align-items: center; gap: 6px; margin-right: 12px; }
.key i { width: 14px; height: 3px; border-radius: 2px; display: inline-block; }
.key i.dot { width: 9px; height: 9px; border-radius: 50%; }

/* ---------- accueil ---------- */
.home-hero { max-width: 1060px; margin: 0 auto; padding: 60px 30px 20px; }
.home-hero h1 { font-size: 56px; }
.home-hero p { color: var(--text-dim); font-size: 18px; max-width: 760px; }
.cards { max-width: 1060px; margin: 20px auto; padding: 0 30px; display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 18px; }
.card {
  display: block; background: var(--panel); border: 1px solid var(--line); border-radius: 14px;
  overflow: hidden; color: var(--text); transition: transform .15s, border-color .15s;
}
.card:hover { transform: translateY(-3px); border-color: var(--blue); text-decoration: none; }
.card.soon { opacity: .5; pointer-events: none; }
.card canvas { display: block; width: 100%; height: 170px; background: #000; }
.card .card-body { padding: 14px 18px 18px; }
.card h3 { margin: 0 0 4px; font-size: 22px; color: var(--text); }
.card .meta { font-size: 12.5px; color: var(--text-faint); }
.card p { font-size: 14px; color: var(--text-dim); margin: 8px 0 0; }
.schedule { max-width: 1060px; margin: 40px auto 80px; padding: 0 30px; }
.schedule table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
.schedule th, .schedule td { text-align: left; padding: 7px 10px; border-bottom: 1px solid var(--line); }
.schedule th { color: var(--text-faint); font-weight: 600; font-size: 12px; text-transform: uppercase; letter-spacing: .06em; }
.schedule tr.done td { color: var(--text); }
.schedule tr.todo td { color: var(--text-faint); }
.schedule tr.exam td { color: var(--red); }
.pill { font-size: 11px; padding: 1px 8px; border-radius: 999px; background: var(--panel-2); color: var(--teal); }

@media (max-width: 1100px) {
  .sidebar { display: none; }
  main.content { padding: 24px 18px 100px; }
  .controls { flex-basis: 100%; border-left: 0; border-top: 1px solid var(--line); max-height: none; }
}
.sidebar a .num { color: var(--text-faint); margin-right: 6px; }
.sidebar a .katex { font-size: 1em; }

/* ---------- « Les objets en jeu » : glossaire détaillé des symboles ---------- */
details.objs {
  margin: 10px 0 18px; border: 1px solid var(--line); border-left: 3px solid var(--teal);
  border-radius: var(--radius); background: rgba(92, 208, 179, 0.035);
}
details.objs > summary {
  cursor: pointer; list-style: none; padding: 8px 14px; font-size: 12px; font-weight: 700;
  letter-spacing: .1em; text-transform: uppercase; color: var(--teal); user-select: none;
}
details.objs > summary::-webkit-details-marker { display: none; }
details.objs > summary::before { content: "▸ "; display: inline-block; transition: transform .2s; }
details.objs[open] > summary::before { transform: rotate(90deg); }
details.objs dl {
  display: grid; grid-template-columns: minmax(110px, max-content) 1fr; gap: 9px 18px;
  margin: 0; padding: 4px 18px 14px;
}
details.objs dt { color: var(--yellow-s); text-align: right; padding-top: 1px; }
details.objs dd { margin: 0; color: var(--text-dim); font-size: 14.5px; line-height: 1.55; }
details.objs dd b { color: var(--text); }
details.objs .ty {
  display: inline-block; font-size: 11px; font-family: var(--font-mono); color: var(--teal);
  background: var(--panel-2); padding: 0 6px; border-radius: 4px; margin-right: 6px; vertical-align: 1px;
}
details.objs .ty .katex { font-size: 1em; }
@media (max-width: 700px) { details.objs dl { grid-template-columns: 1fr; } details.objs dt { text-align: left; } }

/* ---------- page d'entraînement ---------- */
.ex-page { max-width: 1000px; margin: 0 auto; padding: 30px 24px 120px; }
.ex-toolbar { position: sticky; top: 52px; z-index: 20; background: rgba(11,12,16,.92); backdrop-filter: blur(8px); padding: 10px 0; border-bottom: 1px solid var(--line); display: flex; flex-wrap: wrap; gap: 8px 16px; align-items: center; font-size: 13px; }
.ex-toolbar .grp { display: flex; gap: 4px; align-items: center; }
.ex-toolbar .grp > span { color: var(--text-faint); margin-right: 4px; }
#ex-count { color: var(--text-dim); }
#ex-score { margin-left: auto; color: var(--text-dim); }
.ex-card { background: var(--panel); border: 1px solid var(--line); border-radius: 14px; padding: 16px 20px; margin: 18px 0; }
.ex-head { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 8px; }
.ex-num { display: inline-grid; place-items: center; min-width: 26px; height: 26px; border-radius: 50%; background: var(--panel-2); color: var(--yellow-s); font-weight: 700; font-size: 13px; }
.ex-title { font-family: var(--font-serif); font-size: 19px; color: var(--text); }
.ex-head .spacer { flex: 1; }
.ex-type { font-size: 11.5px; font-weight: 600; letter-spacing: .04em; }
.ex-body { color: var(--text); }
.ex-body .katex-display { margin: 10px 0; }
.blank-lbl { display: inline-block; border: 1.5px solid var(--yellow-s); color: var(--yellow-s); border-radius: 4px; padding: 0 6px; font-weight: 700; font-size: .9em; }
.blank-fill { display: inline-block; border: 1.5px solid var(--green); color: var(--green); border-radius: 4px; padding: 0 6px; }
.ex-inputs { display: flex; flex-direction: column; gap: 8px; margin: 12px 0; }
.ex-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; padding: 6px 10px; border-radius: 8px; background: #000; border: 1px solid var(--line); }
.ex-row.ok { border-color: var(--green); } .ex-row.ko { border-color: var(--red); }
.ex-lab { color: var(--yellow-s); font-weight: 700; min-width: 28px; }
.ex-in { flex: 1 1 260px; background: var(--panel-2); border: 1px solid var(--line-2); border-radius: 6px; color: var(--text); padding: 6px 10px; font-family: var(--font-mono); font-size: 13.5px; }
.ex-in:focus { outline: none; border-color: var(--blue); }
.ex-prev { color: var(--text); min-width: 40px; }
.ex-mark { font-weight: 700; min-width: 14px; }
.ex-row.ok .ex-mark { color: var(--green); } .ex-row.ko .ex-mark { color: var(--red); }
.ex-hint { flex-basis: 100%; color: var(--text-faint); font-size: 13px; padding-left: 38px; }
.ex-feedback { font-size: 13.5px; color: var(--text-dim); margin-top: 8px; }
.ex-solution { margin-top: 12px; border-top: 1px dashed var(--line-2); padding-top: 10px; }
.ex-sol-title { font-size: 12px; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; color: var(--green); margin-bottom: 6px; }
.ex-expl { margin-top: 10px; padding: 10px 14px; border-left: 3px solid var(--green); background: rgba(131,193,103,.06); border-radius: 6px; color: var(--text-dim); font-size: 14.5px; }
.ex-intro { color: var(--text-dim); }

/* ---------- page des devoirs ---------- */
.hw-table { border-collapse: collapse; margin: 4px 0 8px; font-size: 13px; width: 100%; }
.hw-table th, .hw-table td { border-bottom: 1px solid var(--line); padding: 4px 8px; text-align: right; }
.hw-table th { color: var(--text-faint); font-weight: 600; }
.hw-table td:first-child, .hw-table th:first-child { text-align: left; }
.hw-q { background: var(--panel); border: 1px solid var(--line); border-radius: 14px; padding: 14px 20px; margin: 20px 0; }
.hw-q > .hw-q-head { display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.hw-q .hw-q-num { font-family: var(--font-serif); font-size: 22px; color: var(--yellow-s); }
.hw-q .hw-q-title { font-family: var(--font-serif); font-size: 19px; color: var(--text); }
.hw-q details.hint > summary { color: var(--purple); }
.hw-q details.hint > summary::before { color: var(--purple); }
.hw-q details.sol > summary { color: var(--green); }
.hw-q details.sol > summary::before { color: var(--green); }
.hw-q details.code > summary { color: var(--blue); }
.hw-q details.code > summary::before { color: var(--blue); }
pre.code { background: #000; border: 1px solid var(--line); border-radius: 8px; padding: 12px 14px; overflow-x: auto; font-family: var(--font-mono); font-size: 12.5px; line-height: 1.5; color: #d6deeb; }
pre.code .cm { color: var(--text-faint); }
.hw-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; margin: 18px 0; }
.hw-card { background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 14px 18px; color: var(--text); display: block; }
a.hw-card:hover { border-color: var(--blue); text-decoration: none; }
.hw-card h3 { margin: 0 0 4px; font-size: 20px; color: var(--text); }
.hw-card .meta { font-size: 12.5px; color: var(--text-faint); }
.hw-card p { font-size: 14px; color: var(--text-dim); margin: 6px 0 0; }
.hw-status { font-size: 11.5px; font-weight: 700; padding: 1px 8px; border-radius: 999px; }
.hw-status.done { color: var(--green); border: 1px solid var(--green); }
.hw-status.todo { color: var(--yellow-s); border: 1px solid var(--yellow-s); }
.hw-status.wait { color: var(--text-faint); border: 1px solid var(--line-2); }

/* ---------- panneau « Affichage » des widgets ---------- */
.disp-btn { padding: 2px 10px; font-size: 12px; }
.disp-panel { display: flex; flex-wrap: wrap; gap: 6px 26px; padding: 8px 14px; border-bottom: 1px solid var(--line); background: #0d0f14; font-size: 12.5px; }
.disp-group { display: flex; flex-wrap: wrap; align-items: center; gap: 4px 14px; }
.disp-title { font-size: 10.5px; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; color: var(--text-faint); margin-right: 2px; }
.disp-item { display: inline-flex; align-items: center; gap: 5px; color: var(--text-dim); cursor: pointer; }
.disp-item input { accent-color: var(--teal); margin: 0; }
.disp-item .katex { font-size: 1em; }

/* ---------- vidéos YouTube recommandées ---------- */
.vids { margin: 10px 0 20px; }
.vids-title { font-size: 11.5px; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; color: var(--red); margin-bottom: 8px; }
.vids-title span { color: var(--text-faint); font-weight: 400; letter-spacing: 0; text-transform: none; margin-left: 6px; }
.vids-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 10px; }
a.vid { display: flex; gap: 10px; align-items: flex-start; background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 8px; color: var(--text); transition: border-color .15s, transform .15s; }
a.vid:hover { border-color: var(--red); text-decoration: none; transform: translateY(-2px); }
.vid-thumb { flex: 0 0 112px; height: 63px; border-radius: 6px; overflow: hidden; background: #1a0b0b; position: relative; display: grid; place-items: center; color: var(--red); font-size: 20px; }
.vid-thumb img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.vid-body { min-width: 0; }
.vid-ch { font-size: 11px; color: var(--text-faint); }
.vid-t { font-size: 13px; line-height: 1.3; color: var(--text); margin: 1px 0 3px; }
.vid-why { font-size: 12px; line-height: 1.35; color: var(--text-dim); }

/* ---------- schéma d'enchaînement (flow) ---------- */
.flow { display: flex; flex-wrap: wrap; align-items: stretch; gap: 6px; margin: 14px 0; }
.flow .st { flex: 1 1 150px; background: var(--panel); border: 1px solid var(--line-2); border-radius: 10px; padding: 8px 10px; font-size: 13px; color: var(--text-dim); }
.flow .st b { display: block; color: var(--yellow-s); font-size: 12px; margin-bottom: 3px; }
.flow .st.goal { border-color: var(--green); } .flow .st.goal b { color: var(--green); }
.flow .ar { align-self: center; color: var(--text-faint); font-size: 18px; }
ol.plan { counter-reset: none; padding-left: 0; list-style: none; }
ol.plan > li { margin: 10px 0; padding: 8px 14px; border-left: 3px solid var(--line-2); background: rgba(255,255,255,0.015); border-radius: 0 8px 8px 0; }
ol.plan > li > .n { color: var(--yellow-s); font-weight: 700; margin-right: 6px; }
ol.plan .why { color: var(--text-faint); font-size: 14px; }
a.offline-ref { cursor: default; }
a.offline-ref:hover { filter: none; text-decoration: none; }

/* ---------- fil conducteur : « où on en est » + tableau des notations ---------- */
.box.road { border-left: 3px solid var(--teal); background: rgba(92, 208, 179, 0.04); }
.box.road > .box-title { color: var(--teal); }
.road-row { display: flex; gap: 12px; align-items: baseline; margin: 5px 0; }
.road-row .rk { flex: 0 0 82px; font-size: 10.5px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; text-align: center; padding: 1px 6px; border-radius: 4px; }
.road-row .rk.ok { color: var(--green); border: 1px solid var(--green); }
.road-row .rk.q { color: var(--red); border: 1px solid var(--red); }
.road-row .rk.go { color: var(--yellow-s); border: 1px solid var(--yellow-s); }
.road-row > div { flex: 1; }
.flow a.st { text-decoration: none; transition: border-color .15s; }
.flow a.st:hover { border-color: var(--yellow-s); }
.flow .st i { display: block; font-style: normal; color: var(--text-faint); font-size: 11.5px; margin-top: 4px; }
.notation-wrap { overflow-x: auto; margin: 10px 0 18px; }
table.notation { border-collapse: collapse; width: 100%; font-size: 14px; }
table.notation th { color: var(--text-faint); font-weight: 600; font-size: 12px; text-align: left; padding: 6px 10px; border-bottom: 1px solid var(--line-2); }
table.notation td { padding: 7px 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
table.notation td:first-child { color: var(--yellow-s); white-space: nowrap; text-align: center; }
table.notation td.where { color: var(--text-faint); font-size: 12.5px; white-space: nowrap; }
table.notation tr.grp td { color: var(--teal); font-size: 11.5px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; text-align: left; padding-top: 14px; border-bottom: 1px solid var(--line-2); }
@media (max-width: 700px) { .road-row { flex-direction: column; gap: 2px; } .road-row .rk { flex: none; } table.notation td.where { white-space: normal; } }

/* ---------- devoirs : énoncé FR / EN ---------- */
.lang-global { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; margin: 14px 0 6px; font-size: 13.5px; }
.lang-global > span:first-child { color: var(--text-dim); margin-right: 4px; }
.lang-global .c-dim { font-size: 12.5px; margin-left: 4px; }
.hw-stmt { margin: 8px 0 12px; }
.hw-stmt::after { content: ""; display: block; clear: both; }
.hw-stmt .lang-switch { float: right; display: flex; margin: 0 0 6px 12px; border: 1px solid var(--line-2); border-radius: 6px; overflow: hidden; }
.hw-stmt .lang-switch button { background: transparent; border: 0; color: var(--text-faint); font: 600 11px var(--font-ui); padding: 3px 8px; cursor: pointer; }
.hw-stmt .lang-switch button + button { border-left: 1px solid var(--line-2); }
.hw-stmt .lang-switch button:hover { color: var(--text); }
.hw-stmt .lang-switch button.on { color: var(--yellow-s); background: rgba(244, 211, 69, 0.08); }
.hw-stmt[data-lang="fr"] .lang-en, .hw-stmt[data-lang="en"] .lang-fr { display: none; }
.hw-stmt .lang-en { border-left: 2px solid var(--blue); padding-left: 12px; }
.hw-stmt .lang-en::before, .hw-stmt[data-lang="both"] .lang-fr::before { display: block; font-size: 10.5px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; margin-bottom: 2px; }
.hw-stmt .lang-en::before { content: "Original (EN)"; color: var(--blue); }
.hw-stmt[data-lang="both"] .lang-fr::before { content: "Reformulation (FR)"; color: var(--text-faint); }
.hw-stmt[data-lang="both"] .lang-en { margin-top: 10px; }
.hw-stmt .lang-fr > p:first-child, .hw-stmt .lang-en > p:first-child { margin-top: 0; }
/* corrigés bilingues : sélecteur au-dessus du bloc dépliable */
.hw-stmt.sol-bi > .lang-switch { float: none; width: max-content; margin: 10px 0 4px auto; }
.hw-stmt.sol-bi .lang-en { border-left: 0; padding-left: 0; }
.hw-stmt.sol-bi .lang-en::before { content: "English"; }
.hw-stmt.sol-bi[data-lang="both"] .lang-fr::before { content: "Français"; }
.hw-stmt.sol-bi[data-lang="fr"] .lang-fr::before, .hw-stmt.sol-bi[data-lang="en"] .lang-en::before { display: none; }
.hw-stmt.sol-bi details.proof { margin-top: 4px; }

/* progression des exercices */
.ex-progress { display: inline-flex; align-items: center; gap: 8px; color: var(--text-dim); }
.pbar { display: inline-block; width: 140px; height: 8px; border-radius: 999px; background: var(--panel-2); border: 1px solid var(--line-2); overflow: hidden; vertical-align: middle; }
.pbar > i { display: block; height: 100%; background: var(--green); transition: width .3s; }
.ex-progress-box { margin: 14px 0 0; font-size: 13.5px; color: var(--text-dim); }
.ex-progress-box summary { cursor: pointer; color: var(--text-faint); }
.ex-progress-box .prow { display: flex; align-items: center; gap: 10px; margin: 6px 0; }
.ex-progress-box .plab { min-width: 110px; }
.ex-progress-box .pbar { width: min(320px, 50vw); }
.ex-progress-box #ex-progress-reset { margin-top: 8px; }
.ex-card.done { border-color: rgba(131,193,103,.55); }
.ex-done { font-size: 12px; font-weight: 700; color: var(--green); cursor: pointer; }
.ex-feedback .btn { margin-left: 6px; }
.ex-progress-box .pnum, .ex-progress { white-space: nowrap; }
.ex-progress-box .plab { flex: 0 0 auto; }

/* ---------- exercices façon sujet d'examen (feuille, cases grises numérotées) ---------- */
.ex-card { background: #fbfaf5; color: #1b1b1f; border: 1px solid #d8d4c8; border-radius: 6px; padding: 26px 34px 20px; box-shadow: 0 2px 14px rgba(0,0,0,.35);
  font-family: KaTeX_Main, 'Latin Modern Roman', 'Computer Modern Serif', 'Times New Roman', serif; font-size: 17px; line-height: 1.55; }
.ex-card .katex { color: #1b1b1f; font-size: 1.05em; }
.ex-card.done { border-color: #7cb26a; box-shadow: 0 0 0 2px rgba(124,178,106,.45), 0 2px 14px rgba(0,0,0,.35); }
.ex-head { border-bottom: 1px solid #ddd8cc; padding-bottom: 8px; margin-bottom: 12px; }
.ex-title { font-family: inherit; font-size: 18px; color: #1b1b1f; }
.ex-num { display: inline; min-width: 0; height: auto; background: none; color: inherit; font-size: inherit; border-radius: 0; }
.ex-type { font-family: var(--font-sans, system-ui); }
.ex-card .src { background: #efece3; }
.ex-card .c-blue { color: #1f6f9a; } .ex-card .c-gold { color: #9a5c12; } .ex-card .c-green { color: #3f7a2c; } .ex-card .c-purple { color: #6b3f86; }
.ex-body { color: #1b1b1f; }
.ex-body p { margin: 0 0 8px; }
.ex-body .katex-display { margin: 12px 0; }
.ex-body b { color: #111; }
.blank-box { display: inline-block; background: #d4d4d4; color: #222; padding: 0 .7em; font-family: var(--font-sans, system-ui); font-size: .85em; border-radius: 1px; line-height: 1.5; }
.ex-card .blank-fill { border: none; background: #cfe6c3; color: #1b1b1f; border-radius: 1px; padding: 0 .4em; }
.ex-inputs { margin: 16px 0 10px; gap: 6px; border-top: 1px solid #ddd8cc; padding-top: 12px; }
.ex-row { background: transparent; border: none; border-radius: 4px; padding: 3px 0; }
.ex-row.ok .ex-in { border-color: #4f9a3a; background: #f1f8ec; } .ex-row.ko .ex-in { border-color: #c4473c; background: #fbefee; }
.ex-lab { color: #1b1b1f; font-weight: 400; min-width: 150px; white-space: nowrap; }
.ex-in { background: #fff; border: 1px solid #b9b4a8; color: #1b1b1f; border-radius: 3px; }
.ex-in:focus { border-color: #1f6f9a; }
.ex-prev { color: #1b1b1f; }
.ex-row.ok .ex-mark { color: #3f7a2c; } .ex-row.ko .ex-mark { color: #b23a30; }
.ex-hint { color: #6a665c; padding-left: 150px; font-size: 14px; }
.ex-feedback { color: #4a473f; font-family: var(--font-sans, system-ui); font-size: 13.5px; }
.ex-card .btn-row .btn { font-family: var(--font-sans, system-ui); }
.ex-card .btn { background: #efece3; color: #1b1b1f; border-color: #c9c4b6; }
.ex-card .btn.primary { background: #1f6f9a; color: #fff; border-color: #1f6f9a; }
.ex-solution { border-top: 1px dashed #c9c4b6; }
.ex-sol-title { color: #3f7a2c; font-family: var(--font-sans, system-ui); }
.ex-expl { background: #eef5e9; border-left-color: #7cb26a; color: #2d2b26; }
.ex-done { color: #3f7a2c; }
.ex-card .hyp { color: #2d2b26; }
.ex-card .claim { font-style: italic; }
@media (max-width: 640px) { .ex-card { padding: 18px 16px; font-size: 16px; } .ex-lab { min-width: 0; } .ex-hint { padding-left: 0; } }
.ex-card .katex-display { overflow-x: auto; overflow-y: hidden; padding: 4px 0; }
.ex-card .katex-display > .katex { font-size: 1em; }