/* Reset and base styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    background-color: #f8f9fa;
}

header, footer {
    background: #333;
    color: #fff;
    padding: 1rem;
    text-align: center;
}

.container {
    display: flex;
    flex: 1;
    flex-direction: column;
    padding: 1rem;
}

nav {
    background: #f4f4f4;
    padding: 1rem;
}

nav ul {
    list-style: none;
}

nav ul li {
    margin: 0.5rem 0;
}

nav ul li a {
    text-decoration: none;
    color: #333;
    font-weight: bold;
}

main {
    background: #fff;
    padding: 1rem;
    flex: 1;
}

@media (min-width: 768px) {
    .container {
        flex-direction: row;
    }
    nav {
        width: 250px;
        flex-shrink: 0;
    }
    main {
        flex: 1;
        padding-left: 1rem;
    }
}