body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: #f4f4f4;
    color: #333;
}

.container {
    width: 90%;
    max-width: 600px;
    margin: 0 auto;
    padding: 20px;
    background: #fff;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

header, footer {
    text-align: center;
    padding: 1em 0;
}

main {
    line-height: 1.6;
}

h1, h2 {
    color: #333;
}

@media screen and (max-width: 600px) {
    .container {
        width: 100%;
        padding: 10px;
    }

    h1 {
        font-size: 1.5em;
    }

    h2 {
        font-size: 1.2em;
    }
}