Add css classes to the tag based on delta name.
function yourtheme_alpha_preprocess_html(&$vars) {
$classes = array();
$contexts = context_active_contexts();
// Add delta names as css classes for <body>
foreach ($contexts as $context) {
if (isset($context->reactions['delta']) && ($delta_name = $context->reactions['delta']['delta_template'])) {
$classes[] = drupal_html_class($delta_name);
}
}
if (!empty($classes)) {
$classes = array_unique($classes);
$vars['attributes_array']['class'] = array_merge($vars['attributes_array']['class'], $classes);
}
}