diff --git a/README.md b/README.md
index d094518..763a2e7 100644
--- a/README.md
+++ b/README.md
@@ -1,42 +1,20 @@
-# A simple number converter 
+# Bit Calculator 
 
-Mostly written by ChatGPT.
-
-# create-svelte
-
-Everything you need to build a Svelte project, powered by [`create-svelte`](https://github.com/sveltejs/kit/tree/main/packages/create-svelte).
-
-## Creating a project
-
-If you're seeing this, you've probably already done this step. Congrats!
+Online: https://xiangpenghao.github.io/calculator/
 
-```bash
-# create a new project in the current directory
-npm create svelte@latest
+A cool screen shot to bait you to click the link:
+![](/dev/screenshot.png)
 
-# create a new project in my-app
-npm create svelte@latest my-app
-```
 
-## Developing
+Allows you to investigate a number in its binary, hexadecimal, and decimal forms. 
+Similar to the Windows calculator in programmer mode, but on Web.
 
-Once you've created a project and installed dependencies with `npm install` (or `pnpm install` or `yarn`), start a development server:
+Could be helpful to debug memory addresses and bit-packed values, common in system programming. 
 
-```bash
-npm run dev
+Note that every number is **64-bit unsigned integer**, because we system programmers don't use [other types](https://www.reddit.com/r/ProgrammerHumor/comments/13gt6co/standagainstfloats/#lightbox).
 
-# or start the server and open the app in a new browser tab
-npm run dev -- --open
-```
-
-## Building
-
-To create a production version of your app:
-
-```bash
-npm run build
-```
-
-You can preview the production build with `npm run preview`.
+Mostly written by ChatGPT.
 
-> To deploy your app, you may need to install an [adapter](https://kit.svelte.dev/docs/adapters) for your target environment.
+#### Contribution
+I don't know much about web / javascript / typescript / svelte / html / css / whatever, I'm open to any contribution.
+I tend to trust your modification, but please at least ask ChatGPT before sending a PR.
diff --git a/dev/dev.md b/dev/dev.md
new file mode 100644
index 0000000..5ce6766
--- /dev/null
+++ b/dev/dev.md
@@ -0,0 +1,38 @@
+# create-svelte
+
+Everything you need to build a Svelte project, powered by [`create-svelte`](https://github.com/sveltejs/kit/tree/main/packages/create-svelte).
+
+## Creating a project
+
+If you're seeing this, you've probably already done this step. Congrats!
+
+```bash
+# create a new project in the current directory
+npm create svelte@latest
+
+# create a new project in my-app
+npm create svelte@latest my-app
+```
+
+## Developing
+
+Once you've created a project and installed dependencies with `npm install` (or `pnpm install` or `yarn`), start a development server:
+
+```bash
+npm run dev
+
+# or start the server and open the app in a new browser tab
+npm run dev -- --open
+```
+
+## Building
+
+To create a production version of your app:
+
+```bash
+npm run build
+```
+
+You can preview the production build with `npm run preview`.
+
+> To deploy your app, you may need to install an [adapter](https://kit.svelte.dev/docs/adapters) for your target environment.
diff --git a/dev/screenshot.png b/dev/screenshot.png
new file mode 100644
index 0000000..f98c240
Binary files /dev/null and b/dev/screenshot.png differ
diff --git a/src/routes/+page.svelte b/src/routes/+page.svelte
index 89d884c..e103869 100644
--- a/src/routes/+page.svelte
+++ b/src/routes/+page.svelte
@@ -174,7 +174,7 @@
 	</div>
 
 	<div class="input-box">
-		<div>Bit bits:</div>
+		<div>Bits:</div>
 		<div>
 			<div class="bit-container">
 				{#each Array.from({ length: 8 }, (_, i) => 7 - i) as i}
@@ -201,6 +201,7 @@
 			</div>
 		</div>
 	</div>
+	<div class="credit"><a href="https://github.com/XiangpengHao/calculator">Code</a></div>
 </div>
 
 <style>
@@ -281,4 +282,7 @@
 		font-size: small;
 		color: #a0a0a0;
 	}
+	.credit {
+		margin-top: 15em;
+	}
 </style>