Underline first letter of shapes

to indicate interactivity

src/index.tsx

@@ -608,7 +608,7 @@ class App extends React.Component<{}, AppState> {
             this.forceUpdate();
           }}
         />
-        {children}
+        <span>{children}</span>
       </label>
     );
   }

src/styles.css

@@ -17,6 +17,14 @@ label {
   margin-right: 10px;
 }
 
+label span {
+  display: inline-block;
+}
+
+label span::first-letter {
+  text-decoration: underline;
+}
+
 input[type="number"] {
   width: 30px;
 }