body {
  background-color: gainsboro;
  font-family: system-ui, sans-serif;
  text-align: center;
  margin: 0;
  padding-top: 20px;
}

h1,
h2 {
  margin: 10px 0;
}

.board {
  width: 350px;
  margin: 20px auto;
}

.sqr {
  width: 100px;
  height: 100px;
  display: inline-block;
  border: 2px solid black;
  font-size: 64px;
  text-align: center;
  line-height: 100px;
  vertical-align: top;
  background-color: white;
  margin: 5px 0;
}

button {
  margin: 10px;
  padding: 10px 20px;
  font-size: 16px;
  background-color: white;
  border: 2px solid black;
  cursor: pointer;
}