demo: Don't show specific theme names.

We don't think theme names like 'cocoa', 'fluent', and 'material' can be
standardized.

#20

demo.html

@@ -80,6 +80,18 @@ <h3>Customization</h3>
   <div><label>Text on track: <std-switch id="tot"></std-switch></label></div>
   <input type=submit>
   </form>
+<div style="--std-control-theme: material">
+  <std-switch></std-switch><std-switch on></std-switch>
+</div>
+
+<div style="--std-control-theme: cocoa">
+  <std-switch></std-switch><std-switch on></std-switch>
+</div>
+
+<div style="--std-control-theme: fluent">
+  <std-switch></std-switch><std-switch on></std-switch>
+</div>
+
 </div>
 
 <div dir=rtl class=container>
@@ -93,26 +105,12 @@ <h3>Customization</h3>
 </div>
 
 <div class=container style="--std-control-theme: match-platform">
-  <p><code>--std-control-theme: match-platform</code></p>
+  <p>An example of <code>--std-control-theme: match-platform</code> behavior.
+  Browsers may apply OS-specific or browser-specific appearance.</p>
   <p id="platform-message">navigator.platform: ...</p>
   <std-switch></std-switch><std-switch on></std-switch>
 </div>
 
-<div class=container style="--std-control-theme: material">
-  <p><code>--std-control-theme: material</code></p>
-  <std-switch></std-switch><std-switch on></std-switch>
-</div>
-
-<div class=container style="--std-control-theme: cocoa">
-  <p><code>--std-control-theme: cocoa</code></p>
-  <std-switch></std-switch><std-switch on></std-switch>
-</div>
-
-<div class=container style="--std-control-theme: fluent">
-  <p><code>--std-control-theme: fluent</code></p>
-  <std-switch></std-switch><std-switch on></std-switch>
-</div>
-
 
 <pre></pre>
 <script>