body, html {
  margin: 0px;
  padding: 0px;
  background-color: lightblue;
  height: 100vh;
}

#naa {
  background-color: red;
  width:100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-content: center;
  justify-content: center;
}
          
#theB {
  width: 100px;
  height: 90px;
  
  margin-left: auto;
  margin-right: auto;
  border-radius: 100%;
}

#TheB:hover {
  border-radius: 0px;
}