Acces admin par icone engrenage + mot de passe 1234

Remplace l'appui long invisible par un petit engrenage discret
dans le coin bas-droit. Clic dessus ouvre un popup de saisie
de mot de passe (1234). Icone quasi invisible (15% opacite).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/css/style.css

@@ -94,13 +94,81 @@ html, body {
   100% { transform: scale(1); opacity: 0.7; }
 }
 
-/* Zone admin invisible */
-.zone-admin {
+/* Bouton admin discret */
+.btn-admin {
   position: absolute;
-  bottom: 0;
-  right: 0;
-  width: 80px;
-  height: 80px;
+  bottom: 12px;
+  right: 12px;
+  width: 40px;
+  height: 40px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 1.2rem;
+  color: rgba(255,255,255,0.15);
+  cursor: pointer;
+  border-radius: 50%;
+  transition: color 0.3s;
+}
+
+.btn-admin:hover, .btn-admin:active {
+  color: rgba(255,255,255,0.4);
+}
+
+/* Popup mot de passe */
+.popup-overlay {
+  position: fixed;
+  top: 0; left: 0;
+  width: 100%; height: 100%;
+  background: rgba(0,0,0,0.7);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 100;
+}
+
+.popup-box {
+  background: var(--fond-carte);
+  border-radius: var(--rayon);
+  padding: 2rem;
+  min-width: 300px;
+  display: flex;
+  flex-direction: column;
+  gap: 1rem;
+  align-items: center;
+  box-shadow: var(--ombre);
+}
+
+.popup-box h3 {
+  color: var(--texte);
+  margin: 0;
+}
+
+.popup-box input {
+  background: var(--fond);
+  border: 2px solid #333;
+  border-radius: 8px;
+  padding: 0.8rem 1.2rem;
+  color: var(--texte);
+  font-size: 1.5rem;
+  text-align: center;
+  letter-spacing: 0.3em;
+  width: 200px;
+  outline: none;
+}
+
+.popup-box input:focus {
+  border-color: var(--primaire);
+}
+
+.popup-actions {
+  display: flex;
+  gap: 1rem;
+}
+
+.mdp-erreur {
+  color: var(--danger);
+  font-size: 0.9rem;
 }
 
 /* === Choix du mode === */