style.css

body{
  background-color: rgb(186, 241, 255);
}

.header{
  color: azure;
  text-align: center;
}

.header h1{
  font-size: 30px;
  color: azure;
  text-align: center;
  padding-top: 20px;
}

.container{
  padding: 0px 10px;
  border-radius: 10px;
  margin: 0 auto;
  max-width: 580px;
  background-color: rgb(128, 147, 255);
  text-align: center;
}

.grid{
  display: flex;
  flex-flow: row wrap;
  justify-content: space-evenly;
  padding-bottom: 20px;
}

.celula{
  width: 170px;
  height: 160px;
  margin: 4px 2px;
  font-size: 100pt;
  padding-top: 10px;
  border-radius: 7px;
  text-align: center;
  background-color: rgb(193, 225, 255);
}

#reset{
  background-color: rgb(0, 20, 199);
  color: azure;
  font-size: 150%;
  border-style: none;
  border-radius: 10px;
  text-align: center;
  padding: 15px 50px;
  margin-bottom: 20px;
  cursor: pointer;
}