html, body {
  background-color: #2B2A28;
  color: white; }

.container {
  width: -webkit-min-content;
  width: -moz-min-content;
  width: min-content;
  margin: 0 auto; }

header {
  text-align: center; }

#score {
  text-align: left; }

.grid {
  border: 5px solid white;
  width: calc(30px * 20); }

.grid:after {
  content: "";
  display: table;
  clear: both; }

.square {
  width: 30px;
  height: 30px;
  float: left; }