diff --git a/client/css/app.css b/client/css/app.css
index 6e753aa..7abbdcf 100644
--- a/client/css/app.css
+++ b/client/css/app.css
@@ -533,3 +533,27 @@ span.tag {
     margin-right: 0.5em;
   }
 }
+
+.overlay-wrapper {
+  position: fixed;
+  left: 0;
+  right: 0;
+  top: 0;
+  bottom: 0;
+  background-color: rgba(0, 0, 0, 0.2);
+  z-index: 100;
+  transition: opacity var(--fade), top var(--fade);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+
+  & > .overlay {
+    max-width: 90%;
+    max-height: 90%;
+    background-color: white;
+    border: 1px solid var(--color1);
+    border-radius: 10px;
+    padding: 10px;
+    box-shadow: 0 0 15px #aaa;
+  }
+}
diff --git a/client/layout.js b/client/layout.js
index c4bc4b1..b2d3ecf 100644
--- a/client/layout.js
+++ b/client/layout.js
@@ -5,6 +5,7 @@ import m from "mithril";
 import menu from "./menu";
 import drawerComponent from "./drawer-component";
 import userMenu from "./user-menu";
+import * as overlay from "./overlay";
 
 const layout = {
   view: vnode => {
@@ -15,7 +16,8 @@ const layout = {
         m(menu, { page: vnode.attrs.page }),
         m(drawerComponent)
       ]),
-      m("#content", { class: `page-${vnode.attrs.page}` }, [vnode.children])
+      m("#content", { class: `page-${vnode.attrs.page}` }, [vnode.children]),
+      overlay.render()
     ];
   }
 };
diff --git a/client/overlay.js b/client/overlay.js
new file mode 100644
index 0000000..9cc6c1e
--- /dev/null
+++ b/client/overlay.js
@@ -0,0 +1,61 @@
+"use strict";
+
+import m from "mithril";
+
+let overlayCallback = null;
+
+function open(callback) {
+  overlayCallback = callback;
+}
+
+function close(callback) {
+  if (callback === overlayCallback) {
+    overlayCallback = null;
+    return true;
+  }
+
+  return false;
+}
+
+function render() {
+  if (overlayCallback)
+    return m(
+      ".overlay-wrapper",
+      {
+        tabindex: 0,
+        onclick: () => {
+          close(overlayCallback);
+        },
+        style: "opacity: 0",
+        oncreate: vnode => {
+          vnode.dom.focus();
+          vnode.dom.style.opacity = 1;
+        },
+        onbeforeremove: vnode => {
+          vnode.dom.style.opacity = 0;
+          return new Promise(resolve => {
+            setTimeout(() => {
+              resolve();
+            }, 500);
+          });
+        }
+      },
+      m(
+        ".overlay",
+        {
+          onclick: e => {
+            e.stopPropagation();
+          }
+        },
+        overlayCallback()
+      )
+    );
+
+  return null;
+}
+
+document.addEventListener("keydown", e => {
+  if (e.keyCode === 27 && close(overlayCallback)) m.redraw();
+});
+
+export { open, close, render };