html, body {
  margin: 0;
  width: 100%;
  height: 100%;
}

#can1 {
  width: 100vw;
  height: 100vh;
  display: block;
}

#div1 {
  position: absolute;
  top: 0px;
  left: 0;
  width: 100%;
  text-align: center;
  color: red;
}
#div2 {
  position: absolute;
  top: 10px;
  right: 0;
  width: 200px;
}
#div3 {
  position: absolute;
  top: 10px;
  left: 10px;
  width: 250px;
}
#div4 {
  position: absolute;
  bottom: 10px;
  right: 10px;
  width: 200px;
 }