body {
    margin: 0;
    font-family: Arial, sans-serif;
}

.container {
    width: 90%;
    max-width: 1000px;
    margin: auto;
}

header {
    background: #222;
    padding: 15px 0;
}

header h1 {
    color: #fff;
    margin: 0;
}

nav ul {
    list-style: none;
    padding: 0;
}

nav ul li {
    display: inline-block;
    margin-right: 15px;
}

nav ul li a {
    color: #fff;
    text-decoration: none;
}

nav ul li a.active {
    border-bottom: 2px solid yellow;
    font-weight: bold;
}

footer {
    background: #222;
    color: #fff;
    text-align: center;
    padding: 15px 0;
    margin-top: 40px;
}