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

body {
    height: 100vh;
    display: flex;
    background: #141423;
}

.memory-game {
    width: 460px;
    height: 360px;
    margin: auto;
    display: flex;
    flex-wrap: wrap;
    perspective: 1000px;
}

.memory-card {
    width: calc(25% - 10px);
    height: calc(33.333% - 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;
}

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

.front-face,
.back-face {
    width: 100%;
    height: 100%;
    padding: 20px;
    position: absolute;
    border-radius: 5px;
    background: #181627;
    backface-visibility: hidden;
}

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

.front-face {
    transform: rotateY(180deg);
}

.header-container{
    width:100%;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    color: white;
    font-size: 25px;
    font-family: Arial, Helvetica, sans-serif;
}
.body-container{
    display: flex;
    width: 100%;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}
.button-container{
    padding-top:30px;
}
.button-container button {
    width:200px;
    height: 70px;
    background: #1b1832;
    border: none;
    color: white;
    font-size: 25px;
}
.hidden{
    display: none;
}
.footer-container{
    padding: 30px;
    width: 40%;
    font-size:15px;
    color: #393b4c;
    font-family: Arial, Helvetica, sans-serif;

}