Check out example codes for "css first child". It will help you in understanding the concepts better.

Code Example 1

:first-child {
	//styles here
}

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

Code Example 2

/*CSS First - forth child*/
:first-child {}

:nth-child(2){}
:nth-child(3){}
:nth-child(4){}

Code Example 3

:first-child {
  css declarations;
}

Code Example 4

:first-child {
	//styles here
}

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

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