add basic live demo component

docs/src/layouts/App/prism.scss

@@ -9,6 +9,13 @@ $codeBlue: #89ddff;
 $codeTeal: #80cbc4;
 $codePurple: #c792ea;
 
+.prism-editor__textarea {
+  background: transparent;
+  border: 0;
+}
+
+.prism-editor__textarea,
+.prism-editor__editor,
 code[class*="language-"],
 pre[class*="language-"] {
   position: relative;
@@ -221,4 +228,4 @@ pre[class*="language-"].language-scss > code {
   &::after {
     display: none;
   }
-}
+}