diff --git a/data/shell.html b/data/shell.html
new file mode 100644
index 0000000..8847965
--- /dev/null
+++ b/data/shell.html
@@ -0,0 +1,82 @@
+<!doctype html>
+<html lang="en">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover, user-scalable=no">
+  <title>text_editor</title>
+  <style>
+    html, body {
+      margin: 0;
+      padding: 0;
+      width: 100%;
+      height: 100%;
+      overflow: hidden;
+      background: #000;
+    }
+    canvas {
+      display: block;
+      width: 100vw;
+      height: 100vh;
+      outline: none;
+      border: 0;
+      background: #000;
+    }
+  </style>
+</head>
+<body>
+  <canvas id="canvas" oncontextmenu="event.preventDefault()" tabindex="0"></canvas>
+  <div id="error-box" style="display:none; position:fixed; left:12px; right:12px; bottom:12px; z-index:9999; box-sizing:border-box; max-height:35vh; overflow:auto; padding:10px 12px; border:1px solid #7f1d1d; border-radius:6px; background:rgba(127,29,29,0.94); color:#fff; font:13px/1.35 monospace; white-space:pre-wrap;"></div>
+  <script>
+    const errorBox = document.getElementById('error-box');
+
+    function showError(message) {
+      const text = String(message || 'Unknown error');
+      console.error(text);
+      errorBox.style.display = 'block';
+      errorBox.textContent = text + '\n\n(click to dismiss)';
+    }
+
+    errorBox.addEventListener('click', () => {
+      errorBox.style.display = 'none';
+      errorBox.textContent = '';
+      Module.canvas.focus();
+    });
+
+    window.addEventListener('error', (event) => {
+      showError(event.error && event.error.stack ? event.error.stack : event.message);
+    });
+
+    window.addEventListener('unhandledrejection', (event) => {
+      const reason = event.reason;
+      showError(reason && reason.stack ? reason.stack : reason);
+      event.preventDefault();
+    });
+
+    var Module = {
+      canvas: document.getElementById('canvas'),
+      print: (text) => console.log(text),
+      printErr: (text) => showError(text),
+      onAbort: (what) => showError('Aborted: ' + what),
+      setStatus: (text) => { if (text) console.log(text); }
+    };
+
+    function resizeCanvasToDisplaySize() {
+      const canvas = Module.canvas;
+      const dpr = window.devicePixelRatio || 1;
+      const w = Math.max(1, Math.floor(window.innerWidth * dpr));
+      const h = Math.max(1, Math.floor(window.innerHeight * dpr));
+      if (canvas.width !== w || canvas.height !== h) {
+        canvas.width = w;
+        canvas.height = h;
+      }
+    }
+
+    window.addEventListener('resize', resizeCanvasToDisplaySize);
+    window.addEventListener('load', () => {
+      resizeCanvasToDisplaySize();
+      Module.canvas.focus();
+    });
+  </script>
+  {{{ SCRIPT }}}
+</body>
+</html>
