Vertical spacing:

• margin

  Law of Proximity: Objects that are closer are perceived to be related

  In other words, set the heading top margin 3rem farther than bottom one

h1 {
  margin: 3rem 0 1rem; /* top = 3, bottom = 1 */
}

• line-height

body {
  font-size: 1rem;  /* fixed line-height */
  line-height: 1.5rem;  /* line-height = 1.5 x font-size (recommanded) */
  line-height: 1.5;
}