<div class="a">
  <div class="b">1</div>
  <div class="c">
    <div class="d">1</div>
    <div class="d">2</div>
    <div class="d">3</div>
  </div>
</div>

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

.a{
  width: 90%;
  margin: auto;
  height: 70%;
  flex-direction: column;
  display: flex;
}

.b{
  width: 100%;
  height: 100%;
  background: #ccc;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 30px;
}

.c{
  display: flex;
  margin-top: 10px;
  height: 50%;
  justify-content: space-between;
}

.d{
  width: 30%;
  height: 100%;
  background: #ccc;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 30px;
}


.d:focus{
  background: lightblue;
  outline: none;
  box-sizing: border-box;
  border: 3px dotted darkblue;
}

document.querySelectorAll(".d").forEach(function (d){
  d.setAttribute("tabindex", "-1"); 
  d.onclick = function (){
   document.querySelector(".b").innerHTML = d.textContent;
  }
})