.container
  h2 title 1
  p Lorem ipsum dolor sit amet.

  h2 title 2
  p Lorem ipsum dolor sit amet.

  h2 title 3
  p Lorem ipsum dolor sit amet.

  h2 title 4
  p Lorem ipsum dolor sit amet.

  h2 title 5
  p Lorem ipsum dolor sit amet.

  p Lorem ipsum dolor sit amet consectetur adipisicing elit. Nihil, beatae.
  p Lorem ipsum dolor sit amet consectetur.

  h2 title 6
  p Lorem ipsum dolor sit amet.
View Compiled 
.container :nth-of-type(3n) {
  background-color: red;
}

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