🖌️ add style option

gui/index.html

@@ -11,6 +11,7 @@
     <!-- <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/water.css@2/out/water.css"> -->
     <!-- <link rel="stylesheet" href="https://unpkg.com/sakura.css/css/sakura.css" type="text/css"> -->
     <!-- <link rel="stylesheet" href="https://cdn.simplecss.org/simple.min.css"> -->
+    <!-- <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@picocss/pico@1/css/pico.classless.min.css"> -->
     <script src="main.js"></script>
     <style>
         label {