Füge Installationshinweis für mobile Geräte hinzu

css/style.css

@@ -173,6 +173,58 @@ body::before {
   100% { transform: translate(-50%,-50%) scale(1.08); }
 }
 
+/* ── Install hint banner ── */
+#install-hint {
+  flex-shrink: 0;
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  padding: 9px 12px 9px 16px;
+  background: rgba(129,140,248,0.07);
+  border-top: 1px solid rgba(129,140,248,0.14);
+  z-index: 50;
+  animation: hintSlide 280ms ease;
+}
+
+#install-hint svg {
+  flex-shrink: 0;
+  color: #818cf8;
+  opacity: 0.8;
+}
+
+#install-hint-text {
+  flex: 1;
+  font-size: 12px;
+  color: rgba(255,255,255,0.55);
+  line-height: 1.45;
+}
+
+#install-hint-text strong {
+  color: rgba(255,255,255,0.85);
+  font-weight: 600;
+}
+
+#install-hint-close {
+  flex-shrink: 0;
+  background: none;
+  border: none;
+  color: rgba(255,255,255,0.25);
+  font-size: 22px;
+  line-height: 1;
+  cursor: pointer;
+  padding: 0 4px;
+  -webkit-tap-highlight-color: transparent;
+  transition: color 150ms;
+}
+
+#install-hint-close:hover,
+#install-hint-close:active { color: rgba(255,255,255,0.6); }
+
+@keyframes hintSlide {
+  from { opacity: 0; transform: translateY(6px); }
+  to   { opacity: 1; transform: translateY(0); }
+}
+
 /* ── Responsive ── */
 @media (min-width: 600px) {
   .finger { width: 80px; height: 80px; }