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

body {
    overflow: hidden;
}

section {
    height: 100vh;
    overflow: hidden;
    background: #091921;
}

section span {
    position: absolute;
    background: white;
    border-radius: 50%;
    background-size: cover;
}

@media screen and (min-width: 300px) and (max-width: 800px) {
    body {
        background: #091921;
    }
    section {
        width: 100%;
    }
}