Class attribute in row definition

Lets you set a class attribute on rows in the layout definition of theme.xml.

Useful for styling a row containing multiple columns. For example adding a background color.

Example:

    <layout name="sidebar">
        <row cols="12" class="content-container">
            <region name="r1-c1">
                <cols>8</cols>
            </region>
            <region name="r1-c2">
                <cols>4</cols>
            </region>
        </row>
    </layout>