.containing-block
  .static-positioned-block I am a statically positioned annd contained by the content-box.
  .absolute-positioned-block I am absolutely positioned and contained by the padding-box.

.containing-block {
  position: relative;
  width: 200px;
  height: 100px;
  padding: 100px;
  background-color: green;
  border: 2px solid black;
  margin: 50px;
}

.static-positioned-block {
  background-color: pink;
  box-sizing: border-box;
  border: 1px solid black;
  width: 100%;
  height: 100%;
  padding: 20px;
}

.absolute-positioned-block {
  position: absolute;
  background-color: coral;
  top: 0;
  left: 0;
  width: 50%;
  padding: 20px;
  border: 1px solid black;
}