style.css

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

body{
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background: #060a1f;
}

.clock h2{
    position: relative;
    display: block;
    color: #fff;
    text-align: center;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: .4em;
    font-size: 1.2em;
    margin-bottom: 5px;
}

.clock #time{
    display: flex;
}

.clock #time div{
    position: relative;
    margin: 0 5px;
    -webkit-box-reflect: below 1px linear-gradient(transparent, #0004);
}

.clock #time div span{
    position: relative;
    width: 100px;
    height: 80px;
    background: #2196f3;
    color: #fff;
    font-weight: 300;
    display: flex;
    justify-content: center;
    z-index: 10;
    align-items: center;
    font-size: 3em;
    box-shadow: 0 0 0 1px rgba(0, 0, 0, .2);
}

.clock #time div span:nth-child(2){
    font-size: .7em;
    height: 30px;
    letter-spacing: .2em;
    font-weight: 500;
    z-index: 9;
    box-shadow: none;
    background: #127fd6;
    text-transform: uppercase;
}

.clock #time div:last-child span{
    background: #ff006a;
}

.clock #time div:last-child span:nth-child(2){
    background: #ec0062;
}