* { box-sizing: border-box;}

#outer{ 
  width:70vmin;
  height: 70vmin;
  margin: 0 auto;
  background-color: grey;
  padding-top:15vmin;
  padding-bottom: 11vmin;
  padding-left: 10vmin;
  padding-right: 15vmin;
}

#second-ring{ 
  width:50vmin;
  height: 50vmin;
  background-color: aqua;
  padding-top:16vmin;
  padding-bottom: 10vmin;
  padding-left: 11vmin;
  padding-right: 15vmin;
}
#innersquare { 
  width:30vmin;
  height: 30vmin;
  padding-top:35vimn;
  padding-bottom: 10px;
  padding-left: 10vmin;
  padding-right: 10vmin;
  background-color: palevioletred;
  padding:20px;
}