<div class="block__wrap">
  <div>
    <div>
      <div>
        <div>
          <div>
            <div>
              <div>
                <div>
                  <div>
                    <div>
                      <div>
                        <div>
                        </div>
                      </div>
                    </div>
                  </div>
                </div>
              </div>
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

.block__wrap {
  width: 400px;
  height: 400px;
  border: 1px solid black;
  margin: 0 auto;
  position: relative;
  resize: both;
  overflow: hidden;
}
.block__wrap  div {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 20px;
  right: 20px;
  background-color: rgba(0,0,255,.05);
}