:first-child {
	color: red;
}

p:first-child {
	color: red;
}

.foo:first-child {
	color: red;
}

.before1 .before2 > :first-child > .during3 {
	color: red;
}

.before1 .before2 > :first-child + * > .during3 {
	color: red;
}

.before1 .before2 > :first-child + * + * > .during3 {
	color: red;
}

.before1 .before2 > :first-child + * + * + .during1.during2 > .during3 {
	color: red;
}