* {
    box-sizing: border-box;
    margin: 0;
}
body {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    font-family: Arial, Helvetica, sans-serif;
}
a {
    color: black;
}
#message_title {
    margin-top: 10vh;
    width: 100%;
    text-align: center;
}

#list_project {
    margin-top: 15vh;
    display: flex;
    flex-wrap: wrap;
    width: 80%;
    justify-content: space-around;
}
.card {
    width: 400px;
    color: black;
}
.card-content {
    padding: 10em 5em;
    position: relative;
    transform-style: preserve-3d;
    text-align: center;
    transition : transform 3s;
}


.card:hover .card-content {
    transform: rotateY(0.5turn);

}
.card-front, .card-back {
    position: absolute;
    transform-style: preserve-3d;
    top:0;
    left:0;
    right:0;
    bottom: 0;
    display: grid;
    align-content: center;
}
.card-front {
    background-color:rgb(146, 185, 202);
    background-size: cover;
    background-position: bottom;
    background-blend-mode: overlay;
}

#rls_front {
    background-image: url(20210521203732j3l8n5763dl31.jpg);
}
#nightsky_front {
    background-image: url(darksite.jpg);
}

.card-front::before {
    content: '';
    position: absolute;
    top:  1em;
    bottom:  1em;
    left:   1em;
    right:  1em;
    border: 3px solid black;
    transform: translateZ(75px);
  }
.card-title {
    transform: translateZ(150px);
}
.card-subtitle {
    transform: translateZ(100px);
}

.card-description {
    transform: translateZ(100px);
}
.card-back {
    transform: rotateY(0.5turn);
    background-color: rgb(55, 61, 83);
    backface-visibility: hidden;
    color: rgb(111, 147, 163);
}