CSS positionの定義方法

.element {
  position: static;
  margin: 5px;
  padding: 10px;
  background-color: #b3e0ff;
}

.element {
  position: relative;
  top: 10px;
  left: 10px;
  background-color: #ffb6c1;
}

.parent {
  position: relative; /* 基準 */
}
.element {
  position: absolute;
  top: 20px;
  right: 20px;
  background-color: #add8e6;
  z-index: 10;
}

.element {
  position: fixed;
  top: 20px;
  right: 20px;
  background-color: #ffdead;
  z-index: 100;
}

.parent {
  height: 300px;
  overflow-y: scroll;
}
.element {
  position: sticky;
  top: 0;
  background-color: #c1ffc1;
  z-index: 50;
}