ArraySliceAnimation.css

body, html {
    padding: 0;
    margin: 0;
    background: #262626;
    font-family: monospace;
    color: #fff;
    height: 100%;
    overflow: hidden;
    display: flex;
}
.container{
    display: block;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
}
.boxes{
    width: 700px;
    height: 80px;
    display: flex;
}
.boxes > .box{
    background: #975353;
    border: 1px solid rgba(0, 0, 0, 0.2);
    line-height: 80px;
    border-radius: 8px;
    flex: 1;
    margin: 0 10px;
    text-align: center;
    font-size: 20px;
    opacity:0;
    -webkit-transform: translateY(-100px);
          transform: translateY(-100px);
}
.boxes .box:nth-of-type(1) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 0.2s;
    animation-delay: 0.2s;
}
.boxes .box:nth-of-type(2) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 0.4s;
    animation-delay: 0.4s;
}
.boxes .box:nth-of-type(3) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 0.6s;
    animation-delay: 0.6s;
}
.boxes .box:nth-of-type(4) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 0.8s;
    animation-delay: 0.8s;
}
.boxes .box:nth-of-type(5) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 1s;
    animation-delay: 1s;
}
.boxes .box:nth-of-type(6) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 1.2s;
    animation-delay: 1.2s;
}
.boxes .box:nth-of-type(7) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 1.4s;
    animation-delay: 1.4s;
}
.boxes .box:nth-of-type(8) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 1.6s;
    animation-delay: 1.6s;
}
.boxes .box:nth-of-type(9) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 1.8s;
    animation-delay: 1.8s;
}
.boxes .box:nth-of-type(10) {
    -webkit-animation: in 0.5s forwards;
    animation: in 0.5s forwards;
    -webkit-animation-delay: 2s;
    animation-delay: 2s;
}
@keyframes in {
  to {
    -webkit-transform: translateY(0px);
            transform: translateY(0px);
    opacity: 1;
  }
}
h2{
    width: auto;
    display: block;
    margin: 0 auto;
    text-align: center;
    font-size: 60px;
    margin-bottom: 5px;
    border: none;
    color: #e3dede;
    border-radius: 20px;
    border-bottom: 2px solid #975353;
}
.boxInput{
    display: flex;
    justify-content: center;
}
.boxInp1{
    position: relative;
    float: left;
}
#numtxt {
    font-size: 42px;
    color: #6da53d;
}
.numBox{
    width: 30px;
    height: 45px;
    margin: 7px;
    background: none;
    border: none;
    font-size: 40px;
    text-align: center;
    line-height: 45px;
    outline: none;
    border-bottom: 1px solid rgba(157, 148, 61, 0.65);
    padding: 0;
    margin: 0;
    margin-top: 50px;
    font-family: monospace;
    font-weight: bold;
    color: #e3dede
}
.num2{
    margin-left: 10px;
}
.boxes > .box.selected {
    background: #33b758;
    transition: .5s;
}