CSS Order of properties

example.css

.declaration-order {

  content: '';

  /* Positioning */
  position: relative;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 1;

  /* Box Model */
  display: block;
  float: left;
  width: 100px;
  height: 100px;

  /* Typography */
  font: 13px "Arial";
  color: #000;

  /* Visual */
  background: #fff;
  border: 1px solid;

  /* Functional */
  transition: 1s ease;

  /* Misc. LESS or Sass */
  &:hover { opacity: 0.5; }
  &:nth-of-type(2) { color: #555; }

}