diff --git a/css/centered-box.css b/css/centered-box.css
index fddbdd6..68787c1 100644
--- a/css/centered-box.css
+++ b/css/centered-box.css
@@ -10,4 +10,16 @@
top: 50%;
-webkit-transform: translate(-50%, -50%);
transform: translate(-50%, -50%);
+}
+
+#centeredBox {
+ opacity: 1;
+ z-index: 2;
+ transition: opacity var(--transition-speed),
+ z-index var(--transition-speed);
+}
+
+#centeredBox.hiddenBox {
+ opacity: 0 !important;
+ z-index: 0 !important;
}
\ No newline at end of file
diff --git a/index.html b/index.html
index 842ab84..ef41809 100644
--- a/index.html
+++ b/index.html
@@ -231,6 +231,7 @@
+