index.css

@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@200;400;600&display=swap');

*{
    box-sizing: border-box;
}
body{
    background-color: black;
    background-image:linear-gradient(#000000, #000000), url("");
    font-family: 'poppins',sans-serif;
    min-height: 100vh;
    background-size: cover;
    background-position: center center;
    margin: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: aliceblue;
}
.countdown-container{
    display: flex;
    flex-wrap: wrap;
}
h2{
    font-size: 3rem;
    margin-top: -10rem;
}
.big-test{
    font-size: 6rem;
    line-height: 1;
    margin: 0 2rem;
}
.countdown-el{
    text-align: center;
}
.countdown-el span{
    font-size: 1.5rem;
}
@media screen and (max-width: 800px) {
    h2{
        font-size: 2rem;
        
    }
    .big-test{
        font-size: 2rem;
        line-height: 1;
        margin: 0 1rem;
    }
    .countdown-el span{
        font-size: 1rem;
    }
}
.text-below{
    font-size: 1rem;
}