space between text lines in html code example

Example 1: line spacing css

line-height: 20px; /* 4px +12px + 4px */
/* OR */
line-height: 1.7em; /* 1em = 12px in this case. 20/12 == 1.666666  */

Example 2: css line spacing

line-height: 1.5;  /* Prefered */

line-height: 1.5em;

line-height: 150%;

line-height: 24px;