* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

body {
  height: 100vh;
  display: flex;
  background: #060AB2;
}

.memory-game {
  width: 640px;
  height: 640px;
  margin: auto;
  display: flex;
  flex-wrap: wrap;
  perspective: 1000px;
}

.memory-card {
  width: calc(25% - 10px);
  height: calc(33% -10px);
  margin: 5px;
  position: relative;
  box-shadow: 1px 1px 1px rgba(0,0,0,.3);
  transform: scale(1);
  transform-style: preserve-3d;
  transition: transform .5s;
}

.front-face,
.back-face {
  width: 100%;
  height: 100%;
  padding: 20px;
  position: absolute;
  border-radius: 5px;
  background: #1C7CCC;
  backface-visibility: hidden;
}

/*Cosi sono una dietro all'altra*/
.front-face {
  transform: rotateY(180deg);
}

.memory-card:active {
  transform: scale(0.97);
  transition: transform .2s;
}

.memory-card.flip {
  transform: rotateY(180deg);
}

.victory {
  width: 100%;
  background-color: #060AB2;
  color: #FFF;
  font-size: 100px;
  position: absolute;
  margin: auto;
  top: 50%;
  transform: translateY(-50%);
  font-family: Helvetica;
  text-align: center;
  border: solid 10px #FFF;
}

.victory h1 {
  margin: 0;
}
.victory button {
  padding: 10px 20px;
  margin: 10px 0 40px 0;
  background-color: #FFF;
  color: #060AB2;
  font-size: 45px;
  border: none;
  box-shadow: 1px 1px 1px rgba(0,0,0,.3);
}

.victory button:hover {
  cursor: pointer;
}

.victory.hidden {
  display: none;
}