I assume you know how to create and reference a css file in CAF, and set the “CSS Class” properties of ProeprtyGroup control to “section-group-bg”, and the css definition is something like:
.section-group-bg{
background-color:#999999;
}
In run-time, PropertyGroup will be rendered as:
<fieldset id="jsfwmp7671:defaultForm:propertyGroup" class="caf-property-group section-group-bg">
<div class="caf-property-group-inner-border">
<div class="portlet-form-label">
Title
<span class="caf-label-separator">:</span>
</div>
<div class="caf-content">
<div id="jsfwmp7671:defaultForm:blockPanel">Anything you set in PropertyGroup will be here</div>
</div>
</div>
</fieldset>
So even you set the class “section-group-bg” correctly, it won’t affect the sub-div, because there is already default style and you can’t modify it. You need the css definition below to change the priority.