body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #0a0a0a, #1a1a2e);
    color: #f4f4f4;
}
header {
    background: #111;
    padding: 1em;
    position: sticky;
    top: 0;
}
header h1 {
    margin: 0;
    font-size: 1.5em;
    color: #00f5d4;
}
nav a {
    margin: 0 1em;
    color: #fff;
    text-decoration: none;
}
section {
    padding: 3em 2em;
}
footer {
    text-align: center;
    padding: 2em;
    background: #111;
    color: #999;
}
.button {
    background: #00f5d4;
    color: #111;
    padding: 0.7em 1.5em;
    text-decoration: none;
    border-radius: 4px;
}