颜色、位置、大小都是可以控制的

* {
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
body {
    font-size: 32px;
    background: #2C1C44;
    font-family: sans-serif;
    color: #FFF;
    font-family: "Playfair Display", serif;
    /*margin: 50px;*/
    margin: 0;
    overflow: hidden;
}
#container {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    perspective: 1500px;

}
#card {
    text-align: center;
    position: relative;
    display: block;
    max-width: 600px;
    width: 600px;
    height: 400px;
    background: #3F2860;
    overflow: hidden;
    box-shadow: 0 0 0.5em rgba(0,0,0,0.4);
    box-shadow: 0.25em 0.25em 0px 0px rgba(0, 0, 0, 0.3);

    transition: 0.6s;
    transform-style: preserve-3d;
    overflow: visible;
}
.text {
    position: absolute;
    top: 0;
    z-index: 5;
    width: 100%;
    height: 100%;
    color: #E49BD4;
    word-wrap: break-word;
}
p {
    font-weight: 400;
    font-size: 1em;
}
h1 {
    width: 100%;
    height: 100%;
    line-height: 350px;
    font-size: 6em;
    font-weight: 900;
    position: relative;
    margin: 0;
}

/* FOR HOVER
---------------------------------------*/
.front, .back {
    background: #3F2860;
    width: 100%;
    height: 100%;
    display: block;
    top: 0;
    left: 0;
    position: absolute;
    backface-visibility: hidden;
    overflow: hidden;
}
.back {
    z-index:10;
    transform: rotateY(180deg);
}
/*
#container:hover #card{
    transform: rotateY(-180deg);
}
*/
.back p {
    line-height: normal;
    position: relative;
    margin:0 5%;
    top: 50%;
    transform: translateY(-50%);
}

@media only screen and (max-width: 600px) {
    h1 { line-height: 175px;}
    #card {
        width: 300px;
        height: 400px;
    }

}
.firework-grp {
    display: block;
    width: 100%;
    height: 100%;
    position: absolute;
    color: white;
    color: #535396;
}
.firework-grp2{
    transform: rotate(180deg);
    color: #2C1C44;
    z-index: 6;
}
.firework-grp3{
    transform: rotate(-75deg);
    color: #E339BD;
    z-index: 7;
}
.firework {
    font-size: 10px;
    display: block;
    width: 8.5em;
    height: 8.5em;
    position: absolute;
}

/* SIZES
------------------------------------*/
.size05 {
    transform: scale(0.5);
}
.size08 {
    transform: scale(0.8);
}
.size13 {
    transform: scale(1.3);
}
.size15 {
    transform: scale(1.5);
}
.size18 {
    transform: scale(1.8);
}
.size20 {
    transform: scale(2);
}

/* POSITION
------------------------------------*/
.pos1 {
    left: 56%;
    top: 65%;
}
.pos2 {
    left: 25%;
    top: 15%;
}
.pos3 {
    left: 50%;
    top: 25%;
}
.pos4 {
    left: -5%;
    top: 50%;
}
.pos5 {
    left: 90%;
    top: 65%;
}
.pos6 {
    left: 35%;
    top: 75%;
}
.pos7 {
    left: 5%;
    top: -5%;
}
.pos8 {
    left: 75%;
    top: 20%;
}



/* FIREWORK
------------------------------------*/
.drops-grp {
    display: block;
    width: 8.5em;
    height: 8.5em;
    position: absolute;
}
.drops-grp2 {
    display: block;
    width: 8.5em;
    height: 8.5em;
    position: absolute;
    transform: rotate(45deg);
}
.drop {
    display: block;
    width: 1em;
    height: 2em;
    overflow: hidden;
    position: absolute;
    opacity: 0;
}
.drop:before {
    content: "";
    display: block;
    width: 1em;
    height: 1em;
    background: currentColor;
    border-radius: 50%;
}
.drop:after {
    content: "";
    display: block;
    position: relative;
    top: -0.4em;
    width: 0;
    height: 0;
    border-top: 1.4em solid currentColor;
    border-left: 0.5em solid transparent;
    border-right: 0.5em solid transparent;
}
.drop-1 {
    left:3.75em;
    top: 0;
    animation: drop1anim 1s ease-in-out infinite;
}
.drop-2 {
    top: 3.25em;
    right: 0;
    animation: drop2anim 1s ease-in-out infinite;
}
.drop-3 {
    left:3.75em;
    bottom: 0;
    animation: drop3anim 1s ease-in-out infinite;
}
.drop-4 {
    top: 3.25em;
    left: 0;
    animation: drop4anim 1s ease-in-out infinite;
}
.firework-2 .drop-1 {
    animation-delay: 0.5s
}
.firework-2 .drop-2 {
    animation-delay: 0.5s
}
.firework-2 .drop-3 {
    animation-delay: 0.5s
}
.firework-2 .drop-4 {
    animation-delay: 0.5s
}

/* FIREWORK DELAY
------------------------------------*/
.delay1 .drop-1 {
    animation-delay: 0.25s
}
.delay1 .drop-2 {
    animation-delay: 0.25s
}
.delay1 .drop-3 {
    animation-delay: 0.25s
}
.delay1 .drop-4 {
    animation-delay: 0.25s
}

.delay2 .drop-1 {
    animation-delay: 0.75s
}
.delay2 .drop-2 {
    animation-delay: 0.75s
}
.delay2 .drop-3 {
    animation-delay: 0.75s
}
.delay2 .drop-4 {
    animation-delay: 0.75s
}

/* keyframes
------------------------------------*/
@keyframes drop1anim {
    0% {
        top:3.25em;
        opacity: 0;
        transform: scale(0.3);
    }
    25% {
        opacity: 0;
    }
    50% {
        opacity: 1;
        transform: scale(1);
    }
    100% {
        top: -0.75em;
        opacity: 0;
        transform: scale(0.3);
    }
}
@keyframes drop2anim {
    0% {
        right:3.75em;
        opacity: 0;
        transform: scale(0.3) rotate(90deg);
    }
    25% {
        opacity: 0;
    }
    50% {
        opacity: 1;
        transform: scale(1) rotate(90deg);
    }
    100% {
        right: -0.25em;
        opacity: 0;
        transform: scale(0.3) rotate(90deg);
    }
}
@keyframes drop3anim {
    0% {
        bottom:3.25em;
        opacity: 0;
        transform: scale(0.3) rotate(180deg);
    }
    25% {
        opacity: 0;
    }
    50% {
        opacity: 1;
        transform: scale(1) rotate(180deg);
    }
    100% {
        bottom: -0.75em;
        opacity: 0;
        transform: scale(0.3) rotate(180deg);
    }
}
@keyframes drop4anim {
    0% {
        left:3.75em;
        opacity: 0;
        transform: scale(0.3) rotate(-90deg);
    }
    25% {
        opacity: 0;
    }
    50% {
        opacity: 1;
        transform: scale(1) rotate(-90deg);
    }
    100% {
        left: -0.25em;
        opacity: 0;
        transform: scale(0.3) rotate(-90deg);
    }
}