Uniformise les boutons du footer BioCID et ajoute des confettis

- Bouton 'Commencer l'exercice 1' déplacé de la slide 1 vers la bottom bar
- Nouveau style .footer-btn uniforme pour les trois boutons (is-primary / is-secondary)
- Effet de confettis au canvas déclenché à l'arrivée sur la slide 6 (comme le TP Nuisibles)

exercices/Exo_BioCID.html

@@ -53,6 +53,26 @@
   flex-wrap: wrap;
   justify-content: center;
 }
+.footer-btn {
+  font-family: 'Syne', sans-serif;
+  font-size: 13px;
+  font-weight: 600;
+  padding: 11px 24px;
+  border-radius: 40px;
+  border: 1.5px solid var(--amber);
+  cursor: pointer;
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  line-height: 1;
+  transition: all 0.2s;
+}
+.footer-btn:hover { transform: translateY(-1px); }
+.footer-btn:active { transform: scale(0.98); }
+.footer-btn.is-primary { background: var(--amber); color: #fff; }
+.footer-btn.is-primary:hover { background: var(--amber-dark); }
+.footer-btn.is-secondary { background: transparent; color: var(--amber-dark); }
+.footer-btn.is-secondary:hover { background: rgba(186,117,23,0.08); }
 .slide-counter {
   position: absolute;
   left: 20px;
@@ -418,12 +438,15 @@
 <div class="bottom-bar" id="bottomBar" style="display:none;">
   <div class="slide-counter" id="slideCounter"></div>
   <div class="bottom-actions">
-    <button class="back-btn" id="backBtn" onclick="goBack()" style="display:none;">← Retour</button>
-    <button class="hint-btn" id="footerHintBtn" onclick="showHintCurrent()" style="display:none;">💡 Voir les indications</button>
-    <button class="btn btn-amber" id="footerNextBtn" onclick="goNext()" style="display:none;">Exercice suivant →</button>
+    <button class="footer-btn is-secondary" id="backBtn" onclick="goBack()" style="display:none;">← Retour</button>
+    <button class="footer-btn is-secondary" id="footerHintBtn" onclick="showHintCurrent()" style="display:none;">💡 Voir les indications</button>
+    <button class="footer-btn is-primary" id="footerNextBtn" onclick="goNext()" style="display:none;">Exercice suivant →</button>
   </div>
 </div>
 
+<!-- Confetti -->
+<canvas id="confettiCanvas" style="position:fixed;inset:0;pointer-events:none;z-index:150;display:none;"></canvas>
+
 <!-- Modal -->
 <div class="modal-overlay" id="modalOverlay" onclick="closeModal(event)">
   <div class="modal" id="modal">
@@ -472,7 +495,6 @@
       <input type="text" id="idFormateur" placeholder="Formateur (facultatif)" autocomplete="off">
     </div>
   </div>
-  <button class="btn btn-amber" onclick="goTo(2)" style="margin-top:1.5rem;">Commencer l'exercice 1 →</button>
 </div>
 
 <!-- ============ SLIDE 2 — EXERCICE 1 ============ -->
@@ -597,6 +619,7 @@ const totalSlides = 6;
 
 // Configuration des boutons du footer par slide
 const slideConfig = {
+  1: { next: 2, nextLabel: "Commencer l'exercice 1 →" },
   2: { hint: 'ex1', next: 3, nextLabel: 'Exercice suivant →' },
   3: { hint: 'ex2', next: 4, nextLabel: 'Exercice suivant →' },
   4: { hint: 'ex3', next: 5, nextLabel: 'Cas de synthèse →' },
@@ -634,6 +657,7 @@ function goTo(n) {
   const sa = next.querySelector('.scroll-area');
   if (sa) sa.scrollTop = 0;
   updateUI();
+  if (n === 6) setTimeout(launchConfetti, 200);
 }
 
 function goBack() {
@@ -704,6 +728,78 @@ function restartAll() {
   updateUI();
 }
 
+function launchConfetti() {
+  const canvas = document.getElementById('confettiCanvas');
+  if (!canvas) return;
+  const ctx = canvas.getContext('2d');
+  canvas.width = window.innerWidth;
+  canvas.height = window.innerHeight;
+  canvas.style.display = 'block';
+
+  const colors = ['#BA7517', '#D85A30', '#F5DFB8', '#633806', '#F0A855', '#E8C068', '#FF8C5A'];
+  const particles = Array.from({ length: 180 }, () => ({
+    x: Math.random() * canvas.width,
+    y: -(Math.random() * canvas.height * 0.5),
+    w: Math.random() * 10 + 5,
+    h: Math.random() * 5 + 3,
+    color: colors[Math.floor(Math.random() * colors.length)],
+    rotation: Math.random() * Math.PI * 2,
+    rotSpeed: (Math.random() - 0.5) * 0.18,
+    vx: (Math.random() - 0.5) * 2.5,
+    vy: Math.random() * 3 + 2,
+    opacity: 1,
+    shape: Math.random() < 0.4 ? 'circle' : 'rect'
+  }));
+
+  let rafId;
+  let start = null;
+  const totalDuration = 3800;
+
+  function draw(ts) {
+    if (!start) start = ts;
+    const elapsed = ts - start;
+
+    ctx.clearRect(0, 0, canvas.width, canvas.height);
+    let active = false;
+
+    particles.forEach(p => {
+      p.x += p.vx;
+      p.y += p.vy;
+      p.vy += 0.04;
+      p.rotation += p.rotSpeed;
+      p.opacity = elapsed < totalDuration * 0.55
+        ? 1
+        : Math.max(0, 1 - (elapsed - totalDuration * 0.55) / (totalDuration * 0.45));
+
+      if (p.y < canvas.height + 20) active = true;
+
+      ctx.save();
+      ctx.translate(p.x, p.y);
+      ctx.rotate(p.rotation);
+      ctx.globalAlpha = p.opacity;
+      ctx.fillStyle = p.color;
+      if (p.shape === 'circle') {
+        ctx.beginPath();
+        ctx.arc(0, 0, p.w / 2, 0, Math.PI * 2);
+        ctx.fill();
+      } else {
+        ctx.fillRect(-p.w / 2, -p.h / 2, p.w, p.h);
+      }
+      ctx.restore();
+    });
+
+    if (active && elapsed < totalDuration * 1.3) {
+      rafId = requestAnimationFrame(draw);
+    } else {
+      canvas.style.display = 'none';
+      ctx.clearRect(0, 0, canvas.width, canvas.height);
+    }
+  }
+
+  if (rafId) cancelAnimationFrame(rafId);
+  rafId = requestAnimationFrame(draw);
+}
+
 function escapeHtml(str) {
   if (!str) return '';
   return str.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');