body {
    margin: 0;
    background: linear-gradient(135deg, #141e30, #243b55);
    color: white;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    overflow: hidden;
    font-family: monospace;
    transition: background 0.5s ease-in-out;
}

#d {
    font-size: 1.5rem;
    white-space: pre;
    color: rgba(255, 255, 255, 0.95);
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.2);
    transition: transform 0.3s ease-in-out;
    margin-bottom: 20px;
}

#marca-agua {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: rgba(255, 255, 255, 0.1);
    font-size: 3.5rem;
    text-align: center;
    pointer-events: none;
    user-select: none;
    z-index: 1000;
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.2);
}

#themebtn {
    position: absolute;
    bottom: 20px;
    right: 20px;
    z-index: 1001;
}

body.dark {
    background: linear-gradient(135deg, #2f2f2f, #4f4f4f);
    color: #fff;
}

body.light {
    background: linear-gradient(135deg, #141e30, #243b55);
    color: white;
}