css first h element

:first-of-type {
	//styles here
}

:first-child {
	//styles here
}

:nth-child(1) { //the benefit of this is you can do it for 2nd, 3rd etc...
	//styles here 
}

p:first-child {
  font-size: 1.5em;
}

p:first-of-type {
  font-size: 1.25em;
}