add copy code button

drake.html

@@ -150,16 +150,21 @@ <h1><a href="index.html" style="text-decoration:none;">Underactuated Robotics</a
   <section><h1>Running on your own machine</h1>
 
     <p>As you get more advanced, you will likely want to run (and extend) these examples on your own machine. On platforms that Drake supports (the latest two releases of Mac and Ubuntu), it should be as simple as running 
-      <pre><code class="python">pip install underactuated --extra-index-url https://drake-packages.csail.mit.edu/whl/nightly/</code></pre>
-    In general, I would strongly recommend running <code>pip</code>
+      <div style="background:#f0f0f0;">
+        <div style="display:flex; justify-content:flex-end;"><button style="padding:10; background-color: transparent; border:0" onclick="copy_code_to_clipboard(this)"><svg stroke="currentColor" fill="none" stroke-width="2" viewBox="0 0 24 24" stroke-linecap="round" stroke-linejoin="round" class="icon-sm" height="1em" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M16 4h2a2 2 0 0 1 2 2v14a2 2 0 0 1-2 2H6a2 2 0 0 1-2-2V6a2 2 0 0 1 2-2h2"></path><rect x="8" y="2" width="8" height="4" rx="1" ry="1"></rect></svg>Copy code</button></div>
+        <pre><code class="bash">pip install underactuated --extra-index-url https://drake-packages.csail.mit.edu/whl/nightly/</code></pre>
+      </div>    In general, I would strongly recommend running <code>pip</code>
     commands in a <a
     href="https://python-guide-cn.readthedocs.io/en/latest/dev/virtualenvs.html">virtualenv</a>.</p>
 
     <p></p>The <drake></drake> website also has a number of alternative <a href="https://drake.mit.edu/installation.html">installation options</a>, including precompiled binaries and Docker instances.</p>
 
     <p>You'll likely want to start from the underactuated root directory.  Then launch your notebook with:</p>
 
-    <div><pre class="highlight"><code>jupyter notebook</code></pre></div>
+    <div style="background:#f0f0f0;">
+      <div style="display:flex; justify-content:flex-end;"><button style="padding:10; background-color: transparent; border:0" onclick="copy_code_to_clipboard(this)"><svg stroke="currentColor" fill="none" stroke-width="2" viewBox="0 0 24 24" stroke-linecap="round" stroke-linejoin="round" class="icon-sm" height="1em" width="1em" xmlns="http://www.w3.org/2000/svg"><path d="M16 4h2a2 2 0 0 1 2 2v14a2 2 0 0 1-2 2H6a2 2 0 0 1-2-2V6a2 2 0 0 1 2-2h2"></path><rect x="8" y="2" width="8" height="4" rx="1" ry="1"></rect></svg>Copy code</button></div>
+      <pre><code class="bash">jupyter notebook</code></pre>
+    </div>
 
     <p>The examples for each chapter that has them will be in a .ipynb file
     right alongside the chapter's html file, and the notebook exercises are