style.css

@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@600;800&display=swap');

:root {
    --color-white: #ffffff;
    --color-black: #202020;
    --color-glass: rgba(255, 255, 255, 0.05);
    --color-shadow: 0 0 25px rgba(0, 0, 0, 0.5);
}

* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    font-family: "Poppins", sans-serif;
    color: var(--color-white);
}

body {
    background-color: black;
}

#confetti-canvas {
    position: absolute;
    top: 0;
    left: 0;
    z-index: 1;
}

.wrapper {
    position: absolute;
    transform: translate(-50%, -50%);
    top: 40%;
    left: 51%;
    font-size: 16px;
}

.heading {
    text-align: center;
    margin-bottom: 4em;
}

.heading h1 {
    font-size: 6.2em;
    font-weight: 800;
    letter-spacing: 0.15em;
    text-shadow: var(--color-shadow);
}

.heading h3 {
    display: inline-block;
    padding: 8px 30px;
    font-size: 1.6em;
    font-weight: 600;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    border-radius: 100vw;
    background-color: var(--color-glass);
    backdrop-filter: blur(12px);
    box-shadow: var(--color-shadow);
}

.countdown {
    display: flex;
    justify-content: center;
    width: 100%;
}

.box {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 25vmin;
    height: 26vmin;
    padding: 1.5em 0;
    margin-top: 350px;
}

span.num {
    position: relative;
    display: block;
    width: 100%;
    padding: 0.7em 0;
    font-size: 3em;
    font-weight: 800;
    letter-spacing: 0.1em;
    text-align: center;
    border-radius: 0.3em;
    background-color: var(--color-glass);
    backdrop-filter: blur(12px);
    box-shadow: var(--color-shadow);
}

span.text {
    display: block;
    position: relative;
    width: 80%;
    bottom: 20px;
    padding: 0.6em 0;
    font-size: 1.1em;
    font-weight: 600;
    text-align: center;
    color: var(--color-black);
    border-radius: 0.35em;
    background-color: var(--color-white);
    box-shadow: var(--color-shadow);
}

.celebration {
    position: absolute;
    top: 80%;
    left: 35%;
}

@media(max-width: 50em) {
    .wrapper {
        font-size: 14px;
    }
    .heading h1 {
        font-size: 4.2em;
    }
    .heading h3 {
        font-size: 1.4em;
    }
    .box {
        width: 20vmin;
        height: 21vmin;
    }
    span.num {
        font-size: 2em;
    }
    span.text {
        font-size: 1em;
    }
}

@media(max-width: 40em) {
    .wrapper {
        font-size: 12px;
    }
    .heading h1 {
        font-size: 4.2em;
    }
    .heading h3 {
        font-size: 1.2em;
        padding: 6px 0;
    }
    .countdown {
        column-gap: 15px;
    }
    .box {
        width: 15vmin;
        height: 16vmin;
        margin-top: 350px;
    }
    span.num {
        font-size: 1.5em;
    }
    span.text {
        font-size: 0.6em;
        width: 100%;
    }
    .celebration {
        top: 65%;
        left: 8%;
    }
}