style.css

* {
  box-sizing: border-box;
}

body {
  font-family: Arial, Tahoma, sans-serif;
}

.info-container {
  width: 1080px;
  margin: 20px auto 0;
  background-color: #f6f6f6;
  padding: 20px;
  font-size: 24px;
  overflow: hidden;
  border: 2px solid #2196f3;
}

.info-container .name {
  float: left;
  width: 50%;
}

.info-container .tries {
  float: right;
  width: 50%;
  text-align: right;
}

.memory-game-blocks {
  display: flex;
  width: 1100px;
  flex-wrap: wrap;
  margin: 20px auto;
}

.memory-game-blocks .game-block {
  height: 200px;
  transition: transform 0.5s;
  transform-style: preserve-3d;
  cursor: pointer;
  position: relative;
  flex: 1 0 200px;
  margin: 0 10px 20px;
}

.memory-game-blocks .game-block .front {
  background-color: #333;
  line-height: 200px;
}

.memory-game-blocks .game-block .back {
    background-color: #607D8B;
    transform: rotateY(180deg);
}

.memory-game-blocks .game-block .back {
    background-color: #607D8B;
    transform: rotateY(180deg);
}