body {
    margin: 0;
    background: #0d1117;
    color: white;
    font-family: Poppins, sans-serif;
}

header {
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(10px);
    padding: 20px 40px;
    display: flex;
    justify-content: space-between;
    position: sticky;
    top: 0;
}