Fast way to check vertical rhythm (for 24px line-height)

vertical-rhytm__checker.css

/**
 * By Zell Liew
 * from http://zellwk.com/blog/web-typography-broken/
 */

.vertical-rhytm__checker {
  background-image: repeating-linear-gradient(to bottom, transparent 0px, transparent 23px, red 23px, red 24px);
  background-position: 0 -6px; /* Moves baseline grid */
}