add back game over from chest

css/style.css

@@ -102,6 +102,48 @@ canvas {
   font-weight: 600;
 }
 
+.game-over-overlay {
+  position: absolute;
+  inset: 0;
+  z-index: 3;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 10px;
+  background: rgba(0, 0, 0, 0.78);
+  text-align: center;
+  padding: 20px;
+}
+
+.game-over-overlay[hidden] {
+  display: none;
+}
+
+.game-over-image {
+  width: min(70%, 460px);
+  max-height: 52vh;
+  object-fit: contain;
+  border-radius: 12px;
+  border: 1px solid rgba(255, 255, 255, 0.22);
+  box-shadow: 0 14px 32px rgba(0, 0, 0, 0.45);
+}
+
+.game-over-text {
+  margin-top: 4px;
+  font-size: clamp(24px, 4vw, 40px);
+  font-weight: 700;
+  color: #f3f7ff;
+  text-transform: uppercase;
+  letter-spacing: 0.08em;
+}
+
+.game-over-subtext {
+  font-size: 14px;
+  color: #c9d8ea;
+  letter-spacing: 0.05em;
+}
+
 .control-panel {
   padding: 16px;
   overflow-y: auto;