Thicker border every nth table row

Question

Hi all ... I want to separate rows in a large-ish table with thicker borders every (I'm thinking 5?) rows.  Been trying stuff but I think my brain is fried.  Anyone got ideas?

Comments

p.s. here is what I currently have.  It's very close, but it includes the label row in its count so doesn't look even.

<style>
#[% QuestionName() %]_div .inner_table > tbody > tr:nth-child(6n+0) {
    border-bottom: 2px solid black;
}
</style>

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I HAVE IT!!!  By changing the (6n+0) to (5n+1)  it skips the header row and counts down 5 from there.