*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
    background-color: #2b2b2b;
}

.container {
  width: 1440px;
  margin: 0 auto;
  padding: 0 15px;
}

.blocks-container {
  position: relative;
  display: flex;
  justify-content: center;
  justify-self: center;
  margin-top: 200px;
  width: 600px;
  height: 600px;
  border: 1px solid red;
}

.block1,
.block2,
.block3 {
  width: 250px;
  height: 250px;
  position: absolute;
  border: 1px solid black
}

.red {
  background-color: red;
  left: 0;
}

.blue {
  background-color: blue;
  top: 200px;
  z-index: 1;
}

.green {
  background-color: green;
  right: 0;
  bottom: 0;
}