app.html
<div class="flex-vert">
<div class="flex-shrink section top">
code editor
</div>
<div class="flex-horiz">
<code-editor style="min-width: 50%; max-width: 50%;"></code-editor>
<output-frame></output-frame>
</div>
<div class="flex-shrink section bottom">methods: rect, box, center, width, height</div>
</div>
<notification-bubbles></notification-bubbles>