Update README.md to be complete

Use similar copy as https://google.github.io/mesop/

Author: wwwillchen

README.md

@@ -1,9 +1,74 @@
-Disclaimer: _This is not an officially supported Google product._
+# Mesop: Build delightful web apps quickly in Python 🚀
 
-# Mesop
+### Used at Google for rapid internal app development
 
-Mesop is a Python-based UI framework that allows you to rapidly build web demos. Engineers without frontend experience can build web UIs by writing idiomatic Python code.
+Mesop is a Python-based UI framework that allows you to rapidly build web apps like demos and internal apps:
 
-## Status
+**Intuitive for UI novices ✨**
 
-Note: Mesop is under development.
+- Write UI in idiomatic Python code
+- Easy to understand reactive UI paradigm
+- Ready to use components
+
+**Frictionless developer workflows 🏎️**
+
+- Hot reload so the browser automatically reloads and preserves state
+- Edit your UI code directly in the browser using the visual editor
+
+**Flexible for delightful demos 🤩**
+
+- Build custom UIs _without_ writing Javascript/CSS/HTML
+- Compose your UI into components, which are just Python functions
+
+**Edit your UI directly in the browser using the Visual Editor 🪄**
+
+[![Visual Editor](https://img.youtube.com/vi/tvbO-Lqq_TA/0.jpg)](https://www.youtube.com/watch?v=tvbO-Lqq_TA)
+
+## Write your first Mesop app in less than 10 lines of code...
+
+[Demo app](https://mesop-y677hytkra-uc.a.run.app/text_io)
+
+```python
+import time
+
+import mesop as me
+import mesop.labs as mel
+
+
+@me.page(path="/text_io", title="Text I/O Example")
+def app():
+  mel.text_io(
+    upper_case_stream,
+    title="Text I/O Example",
+  )
+
+
+def upper_case_stream(s: str):
+  yield s.capitalize()
+  time.sleep(0.5)
+  yield s.capitalize() + "foo"
+```
+
+</div>
+
+## Try it
+
+**Step 1:** Install it
+
+```sh
+$ pip install mesop
+```
+
+**Step 2:** Copy the example above into `main.py`
+
+**Step 3:** Run the app
+
+```sh
+$ mesop main.py
+```
+
+Learn more in [Getting Started](./getting_started.md).
+
+## Disclaimer
+
+_This is not an officially supported Google product._