circadian_css_animation.php

	// ============================================================================
	// Optional:
	// Select a random picture from different time-of-day sets
	// selected choice is loaded into $headerImageName for use in your page
	// ============================================================================
		
	// default to the daytime set
	$activePicSet = $dayPics;
	
	switch($nowSecond){
		case $nowSecond >= $sun['civil_twilight_end']:
				//NIGHT TIME
				$activePicSet = $nightPics;
			break;
	
		case $nowSecond <= $sun['sunrise']:
				//DAWN
				$activePicSet = $sunrisePics;
			break;
		
		case $nowSecond > $sun['sunset'] 
			&& 
			$nowSecond < $sun['civil_twilight_end'] :
				//SUNSET
				$activePicSet = $sunsetPics;
			break;	
			
		case $nowSecond > $sun['sunrise'] 
			&& 
			$nowSecond < $sun['sunset'] :
		default:
				//DAY
				$activePicSet = $dayPics;
			break;
	}
	
	// choose at random from the active pic set
	$headerImageName = $activePicSet[array_rand($activePicSet)];