This reference demonstrates the standardized HTML structure for the OS/2 Warp theme.
<div class="window">
<div class="title-bar">
<div class="title-bar-left">
<div class="system-menu"></div>
<div class="title-bar-text">Title</div>
</div>
<div class="title-bar-right">
<div class="hide-button"></div>
<div class="max-button"></div>
</div>
</div>
<div class="window-body">...</div>
</div>
<button>Normal</button>
<button class="default">Default</button>
<button disabled>Disabled</button>
<fieldset>
<legend>Legend</legend>
<input type="text">
<label><input type="checkbox" checked> Checkbox</label>
</fieldset>