body {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 90vh;
    background-color: #239ac2;
}

video {
    position: absolute;
    top: 0;
    left: 0;
    min-width: 100%;
    min-height: 100%;
    z-index: -100;
}

.birthdayCard {
    position: relative;
    width: 250px;
    height: 350px;
    cursor: pointer;
    transform-style: preserve-3d;
    transform: perspective(2500px);
    transition: 1s;
}

.birthdayCard:hover {
    transform: perspective(2500px) rotate(5deg);
    box-shadow: inset 100px 20px 100px rgba(0, 0, 0, 0.2), 0 10px 100px rgba(0, 0, 0, 0.5);
}

.birthdayCard:hover .cardFront {
    transform: rotateY(-160deg);
}

.birthdayCard:hover .happy {
    visibility: hidden;
}

.cardFront {
    position: relative;
    background-color: #fff;
    width: 250px;
    height: 350px;
    overflow: hidden;
    transform-origin: left;
    box-shadow: inset 100px 20px 100px rgba(0, 0, 0, 0.2), 30px 0 50px rgba(0, 0, 0, 0.4);
    transition: 0.6s;
}

.happy {
    font-family: Tahoma, sans-serif;
    text-align: center;
    margin: 30px;
    background-image: linear-gradient(120deg, #ffd856 0%, #f98c6e 100%);
    transition: 0.1s;
}

.balloons {
    position: absolute;
}

.balloon-1,
.balloon-2,
.balloon-3,
.balloon-4 {
    position: absolute;
    width: 85px;
    height: 95px;
    border-radius: 50%;
}

.balloon-1 {
    background-color: rgba(255, 40, 90, 0.7);
    left: -10px;
    top: 50px;
}

.balloon-2 {
    background-color: rgba(9, 215, 160, 0.7);
    left: 50px;
    top: 20px;
}

.balloon-3 {
    background-color: rgba(255, 186, 26, 0.7);
    left: 110px;
    top: 50px;
}

.balloon-4 {
    background-color: rgba(12, 122, 159, 0.7);
    left: 170px;
    top: 50px;
}

.balloon-1::before,
.balloon-2::before,
.balloon-3::before,
.balloon-4::before {
    content: "";
    position: absolute;
    width: 1px;
    height: 155px;
    background-color: #ffc848;
    top: 95px;
    left: 43px;
}

.balloon-1::after,
.balloon-2::after,
.balloon-3::after,
.balloon-4::after {
    content: "";
    position: absolute;
    border-right: 7px solid transparent;
    border-left: 7px solid transparent;
    top: 94px;
    left: 37px;
}

.balloon-1::after {
    border-bottom: 10px solid #ff3e6b;
}

.balloon-2::after {
    border-bottom: 10px solid #04b183;
}

.balloon-3::after {
    border-bottom: 10px solid #ffc94c;
}

.balloon-4::after {
    border-bottom: 10px solid #13a9bd;
}

.cardInside {
    position: absolute;
    background-color: #fff;
    width: 250px;
    height: 350px;
    z-index: -1;
    left: 0;
    top: 0;
    box-shadow: inset 100px 20px 100px rgba(0, 0, 0, 0.2);
}

p {
    font-family: "Brush Script MT", cursive;
    margin: 40px;
    color: #333;
}

.name {
    position: absolute;
    left: 150px;
    top: 200px;
    color: #333;
}

.back {
    font-family: Tahoma, sans-serif;
    color: #333;
    text-align: center;
    margin: 30px;
    outline-color: #333;
    outline-style: dotted;
}