* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f4f4f4;
    color: #222;
}

.container {
    max-width: 800px;
    margin: 40px auto;
    padding: 30px;
    background: white;
    border-radius: 8px;
}

h1 {
    margin-top: 0;
}

section {
    margin-top: 30px;
}

select {
    width: 100%;
    max-width: 500px;
    padding: 10px;
    font-size: 16px;
}

#us-population,
#state-details,
#county-details {
    font-size: 18px;
    margin-top: 10px;
}

button {
    margin-top: 30px;
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
}