diff --git a/docs/index.css b/docs/index.css
index 5ad2800..ee64b57 100644
--- a/docs/index.css
+++ b/docs/index.css
@@ -2,7 +2,11 @@ body {
   font-family: sans-serif;
 }
 
-@media(prefers-color-scheme: dark){body{color:white;background-color:#111;}}
+@media(prefers-color-scheme: dark){
+  body{
+    color:white;
+    background-color:#121212;
+  }}
 
 #iframe {
   border: none;
diff --git a/docs/index.html b/docs/index.html
index 98199a2..fce93f7 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -4,9 +4,10 @@
 <meta charset="utf-8"/>
 <meta name="viewport" content="width=device-width, viewport-fit=cover">
 <meta name="description" content="itty bitty things can be conveyed in a link.">
-<meta id="themeColor" name="theme-color">
 <link id="favicon" rel="icon" href='/favicon.svg'>
 <link rel="stylesheet" href="/index.css">
+<meta id="themeColor" name="theme-color" content="white" media="(prefers-color-scheme: light)">
+<meta id="themeColorDark" name="theme-color" content="#121212" media="(prefers-color-scheme: dark)">
 <link rel="manifest" href="/manifest.json">
 <script src="/js/lzma/lzma-d-min.js"></script> 
 <script src="/js/lzma/lzma_worker-min.js"></script>
@@ -16,5 +17,5 @@
 <script nomodule> location.href = "/v1/" + location.hash </script>
 <noscript>itty.bitty requires JavaScript.</noscript>
 </head>
-<iframe id="iframe" sandbox="allow-downloads allow-scripts allow-forms allow-top-navigation allow-popups allow-modals allow-popups-to-escape-sandbox"></iframe>
+<iframe id="iframe" sandbox="allow-same-origin allow-downloads allow-scripts allow-forms allow-top-navigation allow-popups allow-modals allow-popups-to-escape-sandbox"></iframe>
 </html>
diff --git a/netlify/edge-functions/echo.js b/netlify/edge-functions/echo.js
new file mode 100644
index 0000000..3d25ef8
--- /dev/null
+++ b/netlify/edge-functions/echo.js
@@ -0,0 +1,11 @@
+export default async (request, context) => {
+  let url = new URL(request.url);
+  let durl = url.search.substring(1);
+  let components = durl.split(",");
+  let data = components.pop();
+  components = components.shift().split(":");
+  let type = components.pop();
+  return new Response(data, {
+    headers: { "content-type": type},
+  });
+}