#back-tool img:first-child, #forward-tool img:first-child {
	display: block;
}

#back-tool img:last-child, #forward-tool img:last-child {
	display: none;
}

#back-tool.available img:first-child, #forward-tool.available img:first-child {
	display: none;
}

#back-tool.available img:last-child, #forward-tool.available img:last-child {
	display: block;
}