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

body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
}

main {
    background-color: black;
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
}

@media (max-width: 768px) {
    nav ul {
        flex-direction: column;
    }

    nav ul li {
        margin: 0.5rem 0;
    }
}

@media (max-width: 480px) {
    header h1 {
        font-size: 1.5rem;
    }

    nav ul li {
        margin: 0.25rem 0;
    }
}