body {
    font-family: sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    transition: background-color 0.5s, color 0.5s;
}

body.light-mode {
    background: linear-gradient(to right, #6dd5ed, #2193b0);
    color: #333;
}

body.dark-mode {
    background: linear-gradient(to right, #0f2027, #203a43, #2c5364);
    color: #fff;
}